UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported)    June 14, 2011

TC PipeLines, LP

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code (877) 290-2772

Not Applicable

(Former name or former address if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o            Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o            Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o            Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o            Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 1.01               Entry into a Material Definitive Agreement.

On June 14, 2011, TC PipeLines, LP (the “Partnership”) and TC PipeLines GP, Inc., entered into an underwriting agreement (the “Underwriting Agreement”) with J.P. Morgan Securities LLC and SunTrust Robinson Humphrey, Inc., as representatives for the several underwriters, relating to the sale of $350,000,000 aggregate principal amount of the Partnership’s 4.65% Senior Notes due 2021.

The Underwriting Agreement contains customary representations, warranties and agreements of the Partnership and certain affiliates, and customary conditions to closing, indemnification rights, obligations of the parties and termination provisions.

The foregoing description of the Underwriting Agreement is qualified in its entirety by reference to the Underwriting Agreement, a copy of which is filed herewith as Exhibit 1.1, and is incorporated herein by reference.

Item 8.01                                             Other Events.

On June 17, 2011, the Partnership completed its sale of $350,000,000 aggregate principal amount of its 4.65% Senior Notes due 2021.  For further information concerning the notes, refer to the exhibits attached to this report.

Item 9.01                                             Financial Statements and Exhibits.

(d) Exhibits

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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EXHIBIT INDEX

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Exhibit 1.1

Execution Version

TC PipeLines, LP

$350,000,000  4.65% Senior Notes due 2021

UNDERWRITING AGREEMENT

June 14, 2011

J.P. Morgan Securities LLC
SunTrust Robinson Humphrey, Inc.
As Representatives of the several

Underwriters named in Schedule 1 attached hereto

c/o J.P. Morgan Securities LLC
383 Madison Avenue
New York, New York 10179

Ladies and Gentlemen:

TC PipeLines, LP, a Delaware limited partnership (the “Partnership”), proposes to sell to the several underwriters listed on Schedule 1 hereto (the “Underwriters”) $350,000,000 aggregate principal amount of its 4.65% Senior Notes due 2021 (the “Notes”).  The Notes are to be issued under an indenture, to be dated as of June 17, 2011 (the “Base Indenture”), between the Partnership and The Bank of New York Mellon, as trustee (the “Trustee”), as supplemented by the First Supplemental Indenture, to be dated as of June 17, 2011 (the “Supplemental Indenture” and, together with the Base Indenture, the “Indenture”).  J.P. Morgan Securities LLC and SunTrust Robinson Humphrey, Inc. (the “Representatives”) shall act as the representatives of the several Underwriters.

For purposes of this Agreement, (i) TC PipeLines GP, Inc., a Delaware corporation (the “General Partner”), is a wholly owned subsidiary of TransCanada PipeLines Limited, a Canadian corporation (“TransCanada”); (ii) the General Partner is the general partner of the Partnership, TC GL Intermediate Limited Partnership, a Delaware limited partnership (“TCGL Intermediate Partnership”), TC Tuscarora Intermediate Limited Partnership, a Delaware limited partnership (“TCT Intermediate Partnership”), and TC PipeLines Intermediate Limited Partnership, a Delaware limited partnership (“TCP Intermediate Partnership” and, together with TCGL Intermediate Partnership and TCT Intermediate Partnership, the “Intermediate Partnerships”); (iii) the Partnership owns all of the limited partner interests in each of the Intermediate Partnerships; (iv) TCGL Intermediate Partnership owns a 46.45% general partner interest in Great Lakes Gas Transmission Limited Partnership, a Delaware limited partnership (“Great Lakes”); (v) TCT Intermediate Partnership owns (directly and indirectly) a 100% general partner interest in Tuscarora Gas Transmission Company, a Nevada general partnership (“Tuscarora”); and (vi) TCP Intermediate Partnership owns a 25% membership interest in Bison Pipeline LLC, a Delaware limited liability company

(“Bison”), a 25% membership interest in Gas Transmission Northwest LLC, a Delaware limited liability company (“GTN”), a 50% general partner interest in Northern Border Pipeline Company, a Texas general partnership (“NBPC”), and a 100% membership interest in North Baja Pipeline, LLC, a Delaware limited liability company (“North Baja”).  The Partnership and the General Partner are collectively referred to herein as the “TCP Parties.”  The Partnership, the General Partner and the Intermediate Partnerships are collectively referred to herein as the “Partnership Entities.”  Certain terms used herein are defined in Section 21 hereof.

This is to confirm the agreement among the TCP Parties and the Underwriters concerning the purchase of the Notes from the Partnership by the Underwriters.

1.             Representations and Warranties.  Each of the TCP Parties, jointly and severally, represents and warrants to, and agrees with, each Underwriter as set forth below in this Section 1.

(a)           Registration Statement.  The Partnership meets the requirements for use of Form S-3 under the Act and has prepared and filed with the Commission a registration statement (file number 333-166221) on Form S-3, including a related base prospectus dated April 22, 2010 for registration under the Act of the offering and sale of the Notes. Such Registration Statement, including any amendments thereto filed prior to the Applicable Time, has become effective under the Act.  The Partnership may have filed with the Commission, as part of an amendment to the Registration Statement or pursuant to Rule 424(b), one or more Preliminary Prospectuses, each of which has previously been furnished to you.  The Partnership will file with the Commission, in accordance with Rule 424(b), a final prospectus supplement relating to the Notes and a related base prospectus that will be part of the registration statement.  As filed, such final prospectus supplement shall contain all information required by the Act and the rules thereunder, and, except to the extent the Representatives shall agree in writing to a modification, shall be in all substantive respects in the form furnished to you prior to the Applicable Time or, to the extent not completed at the Applicable Time, shall contain only such specific additional information and other changes (beyond that contained in the Base Prospectus and any Preliminary Prospectus) as the Partnership has advised you, prior to the Applicable Time, will be included or made therein.  The Registration Statement, at the Applicable Time, meets the requirements set forth in Rule 415(a)(1)(x).  The initial Effective Date of the Registration Statement was not more than three years before the Applicable Time.

Any reference in this Agreement to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Final Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 that were filed under the Exchange Act on or before the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any Preliminary Prospectus or the Final Prospectus, as the case may be; and any reference to the terms “amend,” “amendment” or “supplement” with respect to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Final Prospectus shall be deemed to refer to and include the filing of any document under the Exchange Act after the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any

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Preliminary Prospectus or the Final Prospectus, as the case may be, deemed to be incorporated therein by reference.

(b)           No Material Misstatement or Omission in Final Prospectus or Registration Statement.  On the Effective Date, the Registration Statement did or will, and when the Final Prospectus is first filed in accordance with Rule 424(b) and on the Closing Date (as defined herein) the Final Prospectus (and any supplement thereto) will, comply in all material respects with the applicable requirements of the Act and the Exchange Act and the respective rules thereunder; on each Effective Date and at the Applicable Time, the Registration Statement did not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading; and, on the date of any filing pursuant to Rule 424(b) and on the Closing Date, the Final Prospectus (together with any supplement thereto) will not include any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that the TCP Parties make no representations or warranties as to the information contained in or omitted from the Registration Statement or the Final Prospectus (or any supplement thereto) in reliance upon and in conformity with information furnished in writing to the Partnership by or on behalf of any Underwriter through the Representatives specifically for inclusion in the Registration Statement or the Final Prospectus (or any supplement thereto), it being understood and agreed that the only such information furnished by or on behalf of any Underwriters consists of the information described as such in Section 8(b) hereof.  Each of the statements made by the Partnership in such documents within the coverage of Rule 175(b) under the Act, including (but not limited to) any statements with respect to the anticipated ratio of taxable income to distributions, was made or will be made with a reasonable basis and in good faith.

(c)           Incorporated Documents Comply As to Form.  The Incorporated Documents heretofore filed with the Commission, when they were filed, conformed in all material respects to the requirements of the Exchange Act and did not, as of the time each such document was filed, contain an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements made, in the light of the circumstances under which they were made, not misleading.  Any further Incorporated Documents so filed will, when they are filed, conform in all material respects to the requirements of the Exchange Act and will not, as of the time each such document is filed, contain an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements made, in the light of the circumstances under which they were made, not misleading.

(d)           No Material Misstatement or Omission in Pricing Disclosure Package.  The Pricing Disclosure Package did not, as of the Applicable Time, contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.  The preceding sentence does not apply to statements in or omissions from the Pricing Disclosure Package based upon and in conformity with written information furnished to the Partnership by any Underwriter through the Representatives specifically

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for use therein, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in Section 8(b) hereof.

(e)           Not an Ineligible Issuer.  (i) At the earliest time after the filing of the Registration Statement that the Partnership or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2)) and (ii) as of the Applicable Time (with such date being used as the determination date for purposes of this clause (ii)), the Partnership was not and is not an Ineligible Issuer (as defined in Rule 405), without taking account of any determination by the Commission pursuant to Rule 405 that it is not necessary that the Partnership be considered an Ineligible Issuer.

(f)            No Conflicts in Issuer Free Writing Prospectus.  Each Issuer Free Writing Prospectus, if any, does not include any information that conflicts with the information contained in the Registration Statement, including any document incorporated therein and any prospectus supplement deemed to be a part thereof that has not been superseded or modified.  The foregoing sentence does not apply to statements in or omissions from the Pricing Disclosure Package based upon and in conformity with written information furnished to the Partnership by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in Section 8(b) hereof.

(g)           No Stop Order.  Neither the Commission nor any state or other jurisdiction or other regulatory body has issued, and, to the knowledge of the TCP Parties, is threatening to issue, any stop order under the Act or other order suspending the effectiveness of the Registration Statement (as amended or supplemented) or preventing or suspending the use of any Preliminary Prospectus or the Final Prospectus or suspending the qualification or registration of the Notes for offering or sale in any jurisdiction nor instituted or, to the knowledge of the TCP Parties, threatened to institute proceedings for any such purpose.

(h)           Formation and Qualification of the Partnership Entities, Bison, Great Lakes, GTN and North Baja.  Each of the Partnership Entities, Bison, Great Lakes, GTN and North Baja has been duly formed and is validly existing in good standing as a corporation, limited partnership or limited liability company under the Delaware General Corporation Law (“DGCL”), the Delaware Revised Uniform Limited Partnership Act (“DRULPA”) or the Delaware Limited Liability Company Act (“Delaware LLC Act”), as the case may be, with full corporate or partnership power and authority to own or lease its properties and to conduct the businesses in which it is engaged, and, in the case of the General Partner, TCGL Intermediate Partnership, TCP Intermediate Partnership and TCT Intermediate Partnership, to act as the general partner of the Partnership and each of the Intermediate Partnerships, Great Lakes, NBPC and North Baja, and Tuscarora, respectively, in each case in all material respects as described in the Pricing Disclosure Package and the Final Prospectus.  Each of the Partnership Entities, Bison, Great Lakes, GTN and North Baja is or, at the Closing Date, will be duly registered or qualified as a foreign corporation, limited partnership or limited liability company, as the case may be,

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for the transaction of business under the laws of each jurisdiction in which the character of the business conducted by it or the nature or location of the properties owned or leased by it makes such registration or qualification necessary, except where the failure so to register or qualify would not (i) have a material adverse effect on the condition (financial or otherwise), business, prospects, assets or results of operations of the Partnership and its subsidiaries, taken as a whole (a “Material Adverse Effect”) or (ii) subject the limited partners of the Partnership to any material liability or disability.

(i)            Formation and Qualification of NBPC and Tuscarora.  Each of NBPC and Tuscarora has been duly formed and is validly existing as a general partnership under the laws of the State of Texas and the laws of the State of Nevada, respectively, with full partnership power and authority to own or lease its properties and to conduct its businesses in which it is engaged, in each case in all material respects as described in the Pricing Disclosure Package and the Final Prospectus.  Each of NBPC and Tuscarora is or, at the Closing Date, will be duly registered or qualified as a foreign general partnership for the transaction of business under the laws of each jurisdiction in which the character of the business conducted by it or the nature or location of the properties owned or leased by it makes such registration or qualification necessary, except where the failure so to register or qualify would not (i) have a Material Adverse Effect or (ii) subject the limited partners of the Partnership to any material liability or disability.

(j)            Ownership of the General Partner Interests.  The General Partner is the sole general partner of the Partnership and each of the Intermediate Partnerships with a 1.0% general partner interest in the Partnership and a 1.0101% general partner interest in each of the Intermediate Partnerships; such general partner interests have been duly authorized and validly issued in accordance with the partnership agreement of the Partnership, as amended to date (the “Partnership Agreement”), or the partnership agreements of each of the Intermediate Partnerships, each as amended to date (collectively, the “Intermediate Partnership Agreements”); and the General Partner owns such general partner interests free and clear of all liens, encumbrances (except restrictions on transferability as described in the Final Prospectus), security interests or claims.

(k)           Ownership of the Limited Partner Interests in the Intermediate Partnerships.  The Partnership owns a 98.9899% limited partner interest in each of the Intermediate Partnerships; such limited partner interests have been duly authorized and validly issued in accordance with the applicable Intermediate Partnership Agreement and are fully paid (to the extent required under the applicable Intermediate Partnership Agreement) and nonassessable (except as such nonassessability may be affected by Section 17-607 of the DRULPA); and the Partnership owns such limited partner interests free and clear of all liens, encumbrances, security interests or claims.

(l)            Ownership of Interest in Bison.  TCP Intermediate Partnership owns a 25% membership interest in Bison; such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Bison, as amended to date (the “Bison LLC Agreement”), and is fully paid (to the extent required under the Bison LLC Agreement) and nonassessable (except as such

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nonassessability may be affected by the Delaware LLC Act); and TCP Intermediate Partnership owns such membership interest free and clear of all liens, encumbrances, security interests or claims.

(m)          Ownership of Interest in Great Lakes.  TCGL Intermediate Partnership owns a 46.45% general partner interest in Great Lakes; such general partner interest has been duly authorized and validly issued in accordance with the agreement of limited partnership of Great Lakes, as amended to date (the “Great Lakes Partnership Agreement”); and TCGL Intermediate Partnership owns such general partner interest free and clear of all liens, encumbrances, security interests or claims.

(n)           Ownership of Interest in GTN.  TCP Intermediate Partnership owns a 25% membership interest in GTN; such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of GTN, as amended to date (the “GTN LLC Agreement”), and is fully paid (to the extent required under the GTN LLC Agreement) and nonassessable (except as such nonassessability may be affected by the Delaware LLC Act); and TCP Intermediate Partnership owns such membership interest free and clear of all liens, encumbrances, security interests or claims.

(o)           Ownership of Interest in NBPC.  TCP Intermediate Partnership owns a 50% general partner interest in NBPC; such general partner interest has been duly authorized and validly issued in accordance with the partnership agreement of NBPC, as amended to date (the “NBPC Partnership Agreement”); and TCP Intermediate Partnership owns such general partner interest free and clear of all liens, encumbrances, security interests or claims.

(p)           Ownership of Interest in North Baja.  TCP Intermediate Partnership owns a 100% membership interest in North Baja; such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of North Baja, as amended to date (the “North Baja LLC Agreement”), and is fully paid (to the extent required under the North Baja LLC Agreement) and nonassessable (except as such nonassessability may be affected by the Delaware LLC Act); and TCP Intermediate Partnership owns such membership interest free and clear of all liens, encumbrances, security interests or claims.

(q)           Ownership of Interest in Tuscarora.  TCT Intermediate Partnership owns (directly and indirectly through TC Pipelines Tuscarora LLC) a 100% general partner interest in Tuscarora; such general partner interest has been duly authorized and validly issued in accordance with the partnership agreement of Tuscarora, as amended to date (the “Tuscarora Partnership Agreement”); and TCT Intermediate Partnership owns such general partner interest free and clear of all liens, encumbrances, security interests or claims.

(r)            No Other Subsidiaries.  Other than (i) the Partnership’s ownership interest in the Intermediate Partnerships and (ii) the Intermediate Partnerships’ ownership interests in each of Bison, Great Lakes, GTN, NBPC, North Baja, Tuscarora and TC Pipelines Tuscarora LLC, as applicable, neither the Partnership nor the Intermediate

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Partnerships own, directly or indirectly, any equity or long-term debt securities of any corporation, partnership, limited liability company, joint venture, association or other entity.  Other than its ownership of its partnership interests in the Partnership and each of the Intermediate Partnerships, the General Partner does not own, directly or indirectly, any equity or long-term debt securities of any corporation, partnership, limited liability company, joint venture, association or other entity.

(s)           Conformity of the Indenture and the Notes to Description.  The Indenture and the Notes, when issued and delivered against payment therefor as provided herein and in the Indenture, will conform in all material respects to the descriptions thereof contained in the Pricing Disclosure Package and the Final Prospectus.

(t)            No Preemptive Rights, Registration Rights or Options.  Except as described in the Final Prospectus and the Pricing Disclosure Package, there are no preemptive rights or other rights to subscribe for or to purchase, nor any restriction upon the voting or transfer of, any partnership or equity interests of the Partnership Entities, in each case pursuant to the agreement or certificate of limited partnership, the certificate of incorporation or other incorporation or organizational documents (collectively, the “Organizational Documents”) of any of the Partnership Entities, or any other agreement or instrument to which any such entity is a party or by which any of them may be bound.  Neither the filing of the Registration Statement nor the offering or sale of the Notes as contemplated by this Agreement gives rise to any rights for or relating to the registration of any Notes or other securities of the Partnership other than as provided in the Final Prospectus, the Pricing Disclosure Package and the Partnership Agreement.  There are no outstanding options or warrants to purchase any Notes (except pursuant to this Agreement).

(u)           Authorization, Execution and Delivery of Underwriting Agreement.  This Agreement has been duly authorized, validly executed and delivered by each of the TCP Parties.

(v)           Authorization and Enforceability of the Indenture.  The execution and delivery of, and the performance by the Partnership of its obligations under the Indenture, have been duly and validly authorized by the Partnership.  The Indenture has been duly qualified under the Trust Indenture Act of 1939, as amended (the “Trust Indenture Act”) and, assuming due authorization, execution and delivery thereof by the Trustee, when duly executed and delivered by the Partnership, will constitute a valid and legally binding agreement of the Partnership, enforceable against the Partnership in accordance with its terms, except as enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity.

(w)          Valid Issuance of the Notes.  The Notes have been duly authorized and, when delivered to and paid for by the Underwriters, will have been duly executed by the Partnership in accordance with the provisions of the Indenture.  The Notes, when authenticated, issued and delivered in the manner provided for in the Indenture and delivered against payment of the purchase price for the Notes as provided in this

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Agreement, will constitute valid and legally binding obligations of the Partnership enforceable against the Partnership in accordance with their terms, except as enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity.

(x)            Enforceability of Other Agreements.  The Organizational Documents of each of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora have been duly authorized, validly executed and delivered and are valid and legally binding agreements, enforceable against the parties thereto in accordance with their terms; provided that, with respect to each such agreement, the enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law); and, provided further, that the indemnity, contribution and exoneration provisions contained in any of such agreements may be limited by applicable laws and public policy.

(y)           No Conflicts.  None of the offering and sale by the Partnership of the Notes, the execution, delivery and performance of this Agreement by the TCP Parties, or the consummation of the transactions contemplated hereby or thereby by the TCP Parties (i) conflicts or will conflict with or constitutes or will constitute a violation of the Organizational Documents of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora, (ii) conflicts or will conflict with or constitutes or will constitute a breach or violation of, or a default under (or an event that, with notice or lapse of time or both, would constitute such a default), any indenture, mortgage, deed of trust, loan agreement, lease or other agreement or instrument to which any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora is a party or by which any of them or any of their respective properties may be bound, (iii) violates or will violate any statute, law or regulation or any order, judgment, decree or injunction of any court or governmental agency or body directed to any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora or any of their properties in a proceeding to which any of them or their property is a party, or (iv) results or will result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora, which conflicts, breaches, violations, defaults or liens, in the case of clauses (ii), (iii) or (iv), would, individually or in the aggregate, have a Material Adverse Effect or would materially impair the ability of any of the TCP Parties to perform their obligations under this Agreement.

(z)            No Consents.  No permit, consent, approval, authorization, order, registration, filing or qualification (“consent”) of or with any court, governmental agency or body having jurisdiction over any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora or any of their respective properties is required in connection with the offering and sale by the Partnership of the Notes, the execution, delivery and performance of this Agreement by the TCP Parties, or the consummation by

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any of the TCP Parties of the transactions contemplated by this Agreement, except for such consents required under the Act and state securities or “Blue Sky” laws.

(aa)         No Default.  None of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora is (i) in violation of its Organizational Documents, (ii) in violation of any law, statute, ordinance, administrative or governmental rule or regulation applicable to it or of any order, judgment, decree or injunction of any court or governmental agency or body having jurisdiction over it, or (iii) in breach, default (and no event that, with notice or lapse of time or both, would constitute such a default has occurred or is continuing) or violation in the performance of any obligation, agreement or condition contained in any bond, debenture, note or any other evidence of indebtedness or in any agreement, indenture, lease or other instrument to which it is a party or by which it or any of its properties may be bound, which breach, default or violation, in the case of clause (ii) or (iii), would, if continued, have a Material Adverse Effect, or would materially impair the ability of any of the TCP Parties to perform their obligations under this Agreement.

(bb)         Independent Registered Public Accounting Firm.  The independent registered public accounting firm, KPMG LLP, who has audited the financial statements of the Partnership, Great Lakes and NBPC included in the Pricing Disclosure Package and the Final Prospectus (or any amendment or supplement thereto), is a registered independent public accounting firm with respect to the Partnership, Great Lakes and NBPC, as required by the Act.

(cc)         Financial Statements.  At March 31, 2011, the Partnership had a capitalization as indicated in the Pricing Disclosure Package and the Final Prospectus (and any amendment and supplement thereto).  The historical financial statements (including the related notes and supporting schedules) of the Partnership, Great Lakes and NBPC included in the Pricing Disclosure Package and the Final Prospectus (and any amendment or supplement thereto) comply as to form in all material respects with the requirements of Regulation S-X under the Act and present fairly in all material respects the financial position, results of operations and cash flows of the Partnership, Great Lakes and NBPC on the basis stated therein at the respective dates or for the respective periods which have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) consistently applied through the periods involved, except to the extent disclosed therein.  The summary financial data set forth in the Preliminary Prospectus and the Final Prospectus (and any amendment or supplement thereto) under the caption “Summary Historical and Pro Forma Financial Data” is accurately presented in all material respects and prepared on a basis consistent with the audited historical financial statements from which it has been derived, except to the extent disclosed therein.

(dd)         No Material Adverse Change.  None of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora has sustained, since the date of the latest financial statements included in the Pricing Disclosure Package and the Final Prospectus, any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court

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or governmental action, investigation, order or decree, otherwise than as set forth or contemplated in the Pricing Disclosure Package and the Final Prospectus.  Except as disclosed in the Pricing Disclosure Package and the Final Prospectus (or any amendment or supplement thereto), subsequent to the respective dates as of which such information is given in the Pricing Disclosure Package and the Final Prospectus (or any amendment or supplement thereto), (i) none of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora has incurred any liability or obligation, indirect, direct or contingent, or entered into any transactions, not in the ordinary course of business, that, individually or in the aggregate, is material to the Partnership Entities, taken as a whole, (ii) there has not been any material change in the capitalization or material increase in the short-term debt or long-term debt of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora and (iii) there has not been any material adverse change, or any development involving, individually or in the aggregate, a prospective material adverse change in or affecting the general affairs, condition (financial or other), business, prospects, assets or results of operations of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora.

(ee)         Title to Properties of the Partnership Entities.  None of the Partnership Entities owns in fee simple or under lease any real property or buildings; at the Closing Date , the Partnership Entities will have good and marketable title to all personal property owned by them, in each case free and clear of all liens, encumbrances and defects except such as are described in the Pricing Disclosure Package and the Final Prospectus or such as do not materially affect the value of such property and do not interfere with the use made and proposed to be made of such property by the Partnership Entities.

(ff)           Title to Properties of Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora.  Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora have good and marketable title to all real and personal property necessary to own and operate their respective assets as described in the Pricing Disclosure Package and the Final Prospectus, free and clear of all liens, claims, encumbrances, charges, security interests and defects, except (i) as described in the Pricing Disclosure Package and the Final Prospectus and (ii) such as do not materially interfere with the ownership, operation or benefits of ownership of their assets or materially increase the cost of operation or ownership of their assets, provided that, (a) with respect to the gas transmission pipelines and right-of-way interests related thereto (the “Pipeline Properties”) the foregoing shall only constitute a representation that, except as described in the Pricing Disclosure Package and the Final Prospectus, (x) each of Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora has sufficient title to enable it to use such Pipeline Properties in its business as they have been used in the past and as are proposed to be used in the future, as described in the Pricing Disclosure Package and the Final Prospectus, and (y) any lack of title has not had and will not have any material adverse effect on the ability of Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora to use such Pipeline Properties as they have been used in the past and are proposed to be used in the future, as described in the Pricing Disclosure Package and the Final Prospectus, and will not materially increase the cost of such use, and (b) with respect to any real property, buildings and equipment held under lease by Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora, such real property, buildings and equipment are held by Bison, Great Lakes, GTN, NBPC, North Baja or

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Tuscarora, as applicable, under valid, subsisting and enforceable leases with such exceptions as are not material and do not interfere with the use made and proposed to be made of such real property, buildings and equipment by such person.

(gg)         Permits.  Each of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora has such permits, consents, licenses, franchises, certificates and authorizations of governmental or regulatory authorities (“permits”) as are necessary to own its properties and to conduct its business in the manner described in the Pricing Disclosure Package and the Final Prospectus, subject to such qualifications as may be set forth in the Pricing Disclosure Package and the Final Prospectus and except for such permits the failure of which to have obtained would not have, individually or in the aggregate, a material adverse effect upon the ability of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora to conduct their businesses in all material respects as currently conducted and as contemplated by the Pricing Disclosure Package and the Final Prospectus to be conducted; each of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora has fulfilled and performed all of its material obligations with respect to such permits and no event has occurred which allows, or after notice or lapse of time would allow, revocation or termination thereof or results in any impairment of the rights of the holder of any such permit, except for such failures to perform, revocations, terminations and impairments that would not have a material adverse effect upon the ability of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora to conduct their businesses in all material respects as currently conducted and as contemplated by the Pricing Disclosure Package and the Final Prospectus to be conducted, subject in each case to such qualification as may be set forth in the Pricing Disclosure Package and the Final Prospectus.

(hh)         Books and Records.  The Partnership (i) makes and keeps books, records and accounts that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of assets and (ii) maintains systems of internal accounting controls sufficient to provide reasonable assurances that (A) transactions are executed in accordance with management’s general or specific authorization; (B) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain accountability for assets; (C) access to assets is permitted only in accordance with management’s general or specific authorization; and (D) the recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect to any differences.

(ii)           Disclosure Controls.  The Partnership has established and maintains disclosure controls and procedures (as such term is defined in Rule 13a-15(e) under the Exchange Act) that (i) are designed to ensure that material information relating to the Partnership, including its subsidiary limited partnerships, is made known to the General Partner’s principal executive officer and its principal financial officer by others within those entities, particularly during the periods in which the periodic reports required under the Exchange Act are being prepared; (ii) have been evaluated for effectiveness and presented conclusions regarding such effectiveness in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2010 (the “Partnership 2010 Annual

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Report”); and (iii) as of December 31, 2010, were effective in ensuring that the information required to be disclosed by the Partnership in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms.

(jj)           Internal Control over Financial Reporting. The Partnership’s internal control over financial reporting was effective as of March 31, 2011 to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with U.S. GAAP.  The Partnership is not aware of any significant deficiencies or material weaknesses in its internal control over financial reporting.

(kk)         No Recent Changes to Internal Controls.  Since the date of the latest audited financial statements included or incorporated by reference in the Preliminary Prospectus and the Final Prospectus, there have been no changes in the Partnership’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Partnership’s internal control over financial reporting.

(ll)           Compliance with Sarbanes-Oxley.  The General Partner and the Partnership and all of the General Partner’s directors or officers, in their capacities as such, are in compliance in all material respects with all applicable and effective provisions of the Sarbanes-Oxley Act of 2002 and the rules and regulations promulgated in connection therewith.

(mm)       Tax Returns.  Each of the Partnership Entities, and, to the knowledge of the TCP Parties, each of Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora has filed (or has obtained extensions with respect to) all material federal, state and foreign income and franchise tax returns required to be filed through the date of this Agreement, which returns are complete and correct in all material respects, and has timely paid all taxes shown to be due, if any, pursuant to such returns, other than those (i) that are being contested in good faith and for which adequate reserves have been established in accordance with U.S. GAAP or (ii) that, if not paid, would not have a Material Adverse Effect.

(nn)         ERISA.  With respect to each employee benefit plan, program and arrangement (governed by the laws of Canada or the United States, including, without limitation, any “employee benefit plan” as defined in Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”)) maintained or contributed to by the TCP Parties, or with respect to which the Partnership could incur any liability under ERISA (collectively, the “Benefit Plans”), no event has occurred, in connection with which the Partnership could be subject to any liability under the terms of such Benefit Plan, applicable law (including, without limitation, ERISA and the Internal Revenue Code of 1986, as amended) or any applicable agreement that could have a Material Adverse Effect, or subject the limited partners of the Partnership to any material liability or disability.

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(oo)         Investment Company.  The Partnership is not now, and after issuance and sale of the Notes to be issued and sold by the Partnership hereunder and application of the net proceeds from such sale as described in the Preliminary Prospectus and the Final Prospectus under the caption “Use of Proceeds” will not be, an “investment company” within the meaning of the Investment Company Act of 1940, as amended.

(pp)         Environmental Compliance.  Except as described in the Pricing Disclosure Package and the Final Prospectus, each of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora (i) are in compliance with any and all applicable federal, state and local laws and regulations relating to the protection of human health and safety and the environment or imposing liability or standards of conduct concerning any Hazardous Material (as defined below) (“Environmental Laws”), (ii) have received all permits required of them under applicable Environmental Laws to conduct their respective businesses, (iii) are in compliance with all terms and conditions of any such permits and (iv) do not have any liability in connection with the release into the environment of any Hazardous Material, except as to (i)-(iv) above where such noncompliance with Environmental Laws, failure to receive required permits, failure to comply with the terms and conditions of such permits or liability in connection with such releases would not, individually or in the aggregate, have a Material Adverse Effect.  The term “Hazardous Material” means (A) any “hazardous substance” as defined in the Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended, (B) any “hazardous waste” as defined in the Resource Conservation and Recovery Act, as amended, (C) any petroleum or petroleum product, (D) any polychlorinated biphenyl and (E) any pollutant or contaminant or hazardous, dangerous or toxic chemical, material, waste or substance regulated under or within the meaning of any other Environmental Law.

(qq)         Environmental Review.  In the ordinary course of business, each of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora conducts a periodic review of the effect of Environmental Laws on its business, operations and properties, in the course of which it identifies and evaluates associated costs and liabilities (including, without limitation, any capital or operating expenses required for clean-up, closure of properties or compliance with Environmental Laws or any permit, license or approval, any related constrains on operating activities and any potential liabilities to third parties).  Except as set forth in the Pricing Disclosure Package and the Final Prospectus, there are no costs and liabilities associated with or arising in connection with Environmental Laws as currently in effect (including, without limitation, costs of compliance therewith) which would, individually or in the aggregate, result in a Material Adverse Effect.

(rr)           No Labor Dispute.  Each of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora are in compliance with all federal, state and local employment and labor laws, including, but not limited to, laws relating to non-discrimination in hiring, promotion and pay of employees; no labor dispute with the employees of the Partnership Entities, NBPC or Tuscarora exists or, to the knowledge of the Partnership Entities, is imminent or threatened; and none of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora is aware of any existing,

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imminent or threatened labor disturbance by the employees of any of their principal suppliers, manufacturers or contractors; in any case that would result in a Material Adverse Effect.

(ss)         Insurance.  Each of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora maintains insurance with insurers of recognized financial responsibility covering their properties, operations, personnel and businesses against such losses and risks and in such amounts as are reasonably adequate to protect them and their businesses in a manner consistent with other businesses similarly situated.  None of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora has received notice from any insurer or agent of such insurer that substantial capital improvements or other expenditures will have to be made in order to continue such insurance.  All such insurance is outstanding and duly in force on the date hereof and will be outstanding and duly in force on the Closing Date.  Each of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja and Tuscarora is in compliance with the terms of such policies and instruments in all material respects; and there are no material claims by any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora under any such policy or instrument as to which any insurance company is denying liability or defending under a reservation of rights clause.

(tt)           Litigation.  Except as described in the Pricing Disclosure Package and the Final Prospectus, there is (i) no action, suit or proceeding before or by any court, arbitrator or governmental agency, body or official, domestic or foreign, now pending or, to the best of the TCP Parties’ knowledge, threatened, to which any member of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora is or may be a party or to which the business or property of any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora is or may be subject, (ii) no statute, rule, regulation or order that has been enacted, adopted or issued by any governmental agency or that has been formally proposed by any governmental agency, and (iii) no injunction, restraining order or order of any nature issued by a federal or state court or foreign court of competent jurisdiction to which any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora is or may be subject, that, in the case of clauses (i), (ii) and (iii) above, is reasonably expected to (A) individually or in the aggregate have a Material Adverse Effect, (B) prevent or result in the suspension of the offering and sale of the Notes, or (C) in any manner draw into question the validity of this Agreement.

(uu)         No Distribution of Other Offering Materials.  None of the TCP Parties has distributed and, prior to the later to occur of (i) the Closing Date and (ii) completion of the distribution of the Notes, will not distribute, any prospectus (as defined under the Act) in connection with the offering and sale of the Notes other than the Registration Statement, any Preliminary Prospectus, the Pricing Disclosure Package, the Final Prospectus or other materials, if any, permitted by the Act, including Rule 134.

(vv)         Market Stabilization.  The TCP Parties have not taken, directly or indirectly, any action designed to or that would constitute or that might reasonably be expected to cause or result in, under the Exchange Act or otherwise, stabilization or

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manipulation of the price of any security of the Partnership to facilitate the sale or resale of the Notes.

(ww)       Related Party Transactions.  No relationship, direct or indirect, exists between or among the TCP Parties on the one hand, and the directors, officers, partners, customers or suppliers of the General Partner and its respective affiliates (other than the TCP Parties) on the other hand, which is required to be described in the Pricing Disclosure Package and the Final Prospectus which is not so described.

(xx)          No Omitted Descriptions.  There are no legal or governmental proceedings pending or, to the knowledge of the TCP Parties, threatened or contemplated, against any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora or to which any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora is a party, or to which any of their respective properties or assets is subject, that are required to be described in the Pricing Disclosure Package or the Final Prospectus that are not described as required, and there are no agreements, contracts, indentures, leases or other instruments that are required to be described in the Pricing Disclosure Package or the Final Prospectus or to be filed as an exhibit to the Registration Statement that are not described or filed as required by the Act.

(yy)         FCPA.  None of the Partnership Entities, nor any director or officer, nor to the knowledge of the Partnership, any agent, employee or affiliate of any of the Partnership Entity is aware of or has taken any action, directly or indirectly, that would result in a violation by such persons of the Foreign Corrupt Practices Act of 1977, as amended, and the rules and regulations thereunder (the “FCPA”), including, without limitation, making use of the mails or any means or instrumentality of interstate commerce corruptly in furtherance of an offer, payment, promise to pay or authorization of the payment of any money, or other property, gift, promise to give, or authorization of the giving of anything of value to any “foreign official” (as such term is defined in the FCPA) or any foreign political party or official thereof or any candidate for foreign political office, in contravention of the FCPA; and the Partnership Entities have conducted their businesses in compliance with applicable anti-corruption laws to which they may be subject; and the Partnership Entities and, to the knowledge of the Partnership, their affiliates have instituted and maintain policies and procedures designed to ensure, and which are reasonably expected to continue to ensure, continued compliance therewith.

(zz)          Money Laundering.  The operations of the Partnership Entities are and have been conducted at all times in material compliance with applicable financial recordkeeping and reporting requirements and the money laundering statutes of jurisdictions where the Partnership Entities conduct business and rules and regulations thereunder and any related or similar rules, regulations or guidelines issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving any of the Partnership Entities with respect to the Money Laundering Laws is pending or, to the best knowledge of the Partnership, threatened.

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(aaa)       OFAC.  None of the Partnership Entities, nor any director or officer, nor to the knowledge of the Partnership, any agent, employee or affiliate of any Partnership Entity, is the subject of any sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“OFAC”); and the Partnership will not directly or indirectly use the proceeds of the sale of the Notes, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person or entity, or in an country or territory, that at the time of such financing is the subject of any sanctions administered by OFAC.

Any certificate signed by any officer of any of the TCP Parties and delivered to the Representatives or counsel for the Underwriters in connection with the offering of the Notes shall be deemed a representation and warranty by the TCP Parties, as to matters covered thereby, to each Underwriter.

2.             Purchase and Sale.  Subject to the terms and conditions and in reliance upon the representations and warranties set forth herein, the Partnership agrees to sell to the several Underwriters, and each Underwriter agrees, severally and not jointly, to purchase from the Partnership, the principal amount of Notes set forth opposite such Underwriter’s name in Schedule 1 hereto at a purchase price equal to 99.184% of the principal amount thereof, plus accrued interest, if any, from the Closing Date.

3.             Delivery and Payment.  Delivery of and payment for the Notes shall be made at the offices of Baker Botts L.L.P., 910 Louisiana Street, Houston, Texas 77002, at 10:00 a.m., New York City time, on June 17, 2011, or at such time on such later date not more than three Business Days after the foregoing date as J.P. Morgan Securities LLC shall designate, which date and time may be postponed by agreement between J.P. Morgan Securities LLC and the Partnership or as provided in Section 9 hereof (such date and time of delivery and payment for the Notes being herein called the “Closing Date”).  Payment for the Notes shall be made by wire transfer in same-day funds to the accounts specified by the Partnership against delivery to the Trustee as custodian for the nominee of The Depository Trust Company, for the account of the Underwriters, of one or more global notes representing the Notes.

4.             Offering by Underwriters.  It is understood that the several Underwriters propose to offer the Notes for sale to the public as set forth in the Final Prospectus.

5.             Agreements.  Each of the TCP Parties, jointly and severally, covenants and agrees with the several Underwriters that:

(a)           Registration Statement.  Prior to the termination of the offering of the Notes, the Partnership will not file any amendment of the Registration Statement or supplement to the Base Prospectus or the Final Prospectus or any Rule 462(b) Registration Statement unless the Partnership has furnished you a copy for your review prior to filing and will not file any such proposed amendment or supplement to which you reasonably and timely object.  The Partnership will cause the Final Prospectus, properly completed, and any supplement thereto to be filed in a form approved by the Representatives with the Commission pursuant to the applicable paragraph of Rule

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424(b) within the time period prescribed and will provide evidence satisfactory to the Representatives of such timely filing.  The Partnership will promptly advise the Representatives (i) when the Final Prospectus, and any supplement thereto, shall have been filed (if required) with the Commission pursuant to Rule 424(b) or when any Rule 462(b) Registration Statement shall have been filed with the Commission, (ii) when, prior to termination of the offering of the Notes, any amendment to the Registration Statement shall have been filed or become effective, (iii) of any request by the Commission or its staff for any amendment of the Registration Statement, or any Rule 462(b) Registration Statement, or for any supplement to the Final Prospectus or for any additional information, (iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or any notice that would prevent its use or the institution or threatening of any proceeding for that purpose and (v) of the receipt by the Partnership of any notification with respect to the suspension of the qualification of the Notes for sale in any jurisdiction or the institution or threatening of any proceeding for such purpose.  The Partnership will use its best efforts to prevent the issuance of any such stop order or the occurrence of any such suspension or prevention and, upon such issuance, occurrence or prevention, to obtain as soon as possible the withdrawal of such stop order or relief from such occurrence or prevention, including, if necessary, by filing an amendment to the Registration Statement or a new registration statement and using its best efforts to have such amendment or new registration statement declared effective as soon as practicable.

(b)           Final Term Sheet and Issuer Free Writing Prospectuses.  The Partnership agrees (i) to prepare a final term sheet, containing a description of the final terms of the Notes and the offering thereof, in the form approved by the Representatives and attached as Schedule 2 hereto, and to file such term sheet pursuant to Rule 433 within the time required by such Rule and (ii) not to make any offer relating to the Notes that would constitute an Issuer Free Writing Prospectus without the prior consent of the Representatives.

(c)           Notice of Untrue Statement or Omission in Pricing Disclosure Package.  If there occurs an event or development as a result of which the Pricing Disclosure Package would include an untrue statement of a material fact or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances then prevailing, not misleading, the Partnership will notify promptly the Representatives so that any use of the Pricing Disclosure Package may cease until it is amended or supplemented.

(d)           Amendment of Registration Statement.  If, at any time when, in the opinion of counsel to the Underwriters, a prospectus relating to the Notes is required to be delivered under the Act (including in circumstances where such requirement may be satisfied pursuant to Rule 172), any event occurs as a result of which the Final Prospectus as then supplemented would include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein in the light of the circumstances under which they were made not misleading, or if it shall be necessary to amend the Registration Statement, file a new registration statement or supplement the Final Prospectus to comply with the Act or the Exchange Act or the respective rules

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thereunder, including in connection with use or delivery of the Final Prospectus, the Partnership promptly will (i) notify the Representatives of such event, (ii) prepare and file with the Commission, subject to the second sentence of paragraph (i)(a) of this Section 5, an amendment or supplement or new registration statement which will correct such statement or omission or effect such compliance, (iii) use its best efforts to have any amendment to the Registration Statement or new registration statement declared effective as soon as practicable in order to avoid any disruption in use of the Final Prospectus and (iv) supply any supplemented Final Prospectus to the Underwriters in such quantities as the Underwriters may reasonably request.

(e)           Documents Available.  As soon as practicable, but in any event not later than 90 days after the period covered thereby, the Partnership will make generally available to its security holders and to the Representatives an earnings statement or statements of the Partnership and its subsidiaries which will satisfy the provisions of Section 11(a) of the Act and Rule 158 thereunder.

(f)            Copies of Documents to the Underwriters.  The Partnership will furnish to the Representatives and their counsel, without charge, signed copies of the Registration Statement (including exhibits thereto) and, so long as delivery of a prospectus by an Underwriter or dealer may be required by the Act (including in circumstances where such requirement may be satisfied pursuant to Rule 172), as many copies of each Preliminary Prospectus, the Final Prospectus and each Issuer Free Writing Prospectus and any supplement thereto as the Underwriters may reasonably request.  The Partnership will pay the expenses of printing or other production of all documents relating to the offering.

(g)           Blue Sky Qualifications.  The Partnership will arrange, if necessary, for the qualification of the Notes for sale under the laws of such jurisdictions as the Underwriters may designate, will maintain such qualifications in effect so long as required for the distribution of the Notes and will pay any fee of the Financial Industry Regulatory Authority (“FINRA”), in connection with its review of the offering; provided that in no event shall the Partnership be obligated to qualify to do business in any jurisdiction where it is not now so qualified or to take any action that would subject it to service of process in suits, other than those arising out of the offering or sale of the Notes, in any jurisdiction where it is not now so subject.

(h)           Use of Issuer Free Writing Prospectus.  The TCP Parties agree that, unless they have obtained or will obtain the prior written consent of the Representatives, and each Underwriter, severally and not jointly, agrees with the TCP Parties that, unless it has obtained or will obtain, as the case may be, the prior written consent of the Partnership, it has not made and will not make any offer relating to the Notes that would constitute an Issuer Free Writing Prospectus or that would otherwise constitute a “free writing prospectus” (as defined in Rule 405) required to be filed by the Partnership with the Commission or retained by the Partnership under Rule 433; provided that the prior written consent of the parties hereto shall be deemed to have been given in respect of the free writing prospectuses included in Schedule 3 hereto.  Any such free writing prospectus consented to by the Underwriters or the TCP Parties is hereinafter referred to as a “Permitted Free Writing Prospectus.”  The TCP Parties agree that (x) they have

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treated and will treat, as the case may be, each Permitted Free Writing Prospectus as an Issuer Free Writing Prospectus and (y) they have complied and will comply, as the case may be, with the requirements of Rules 164 and 433 applicable to any Permitted Free Writing Prospectus, including in respect of timely filing with the Commission, legending and record keeping.

(i)            Market Stabilization.  The TCP Parties will not take, directly or indirectly, any action designed to or that would constitute or that might reasonably be expected to cause or result in, under the Exchange Act or otherwise, stabilization or manipulation of the price of any security of the Partnership to facilitate the sale or resale of the Notes.

(j)            Expenses.  The Partnership agrees to pay the costs and expenses relating to the following matters:  (i) the preparation, printing or reproduction and filing with the Commission of the Registration Statement (including financial statements and exhibits thereto), each Preliminary Prospectus, the Pricing Disclosure Package, the Final Prospectus, and each amendment or supplement to any of them; (ii) the printing (or reproduction) and delivery (including postage, air freight charges and charges for counting and packaging) of such copies of the Registration Statement, each Preliminary Prospectus, the Pricing Disclosure Package, the Final Prospectus, and all amendments or supplements to any of them, as may, in each case, be reasonably requested for use in connection with the offering and sale of the Notes; (iii) the preparation, printing, authentication and delivery of certificates for the Notes, including any stamp or transfer taxes in connection with the sale of the Notes; (iv) the printing (or reproduction) and delivery of this Agreement, any blue sky memorandum and all other agreements or documents printed (or reproduced) and delivered in connection with the offering of the Notes; (v) any registration or qualification of the Notes for offer and sale under the Notes or blue sky laws of the several states (including filing fees and the reasonable fees and expenses of counsel for the Underwriters relating to such registration and qualification); (vi) any filings required to be made with FINRA (including filing fees and the reasonable fees and expenses of counsel for the Underwriters relating to such filings); (vii) the transportation and other expenses incurred by or on behalf of Partnership representatives in connection with presentations to prospective purchasers of the Notes; (viii) the fees and expenses of the Partnership’s accountants and the fees and expenses of counsel (including local and special counsel) for the Partnership; (ix) any fees charged by rating agencies for rating the Notes; (x) the fees and expenses of the Trustee and paying agent (including related fees and expenses of any counsel for such parties) and (xi) all other costs and expenses incident to the performance by the Partnership of its obligations hereunder.

(k)           Clear Market.  During the period from the date hereof through and including the business day following the Closing Date, the Partnership will not, without the prior written consent of the Representatives, offer, sell, contract to sell or otherwise dispose of any debt securities issued by the TCP Parties.

6.             Conditions to the Obligations of the Underwriters.  The obligations of the Underwriters to purchase the Notes shall be subject to the accuracy of the representations and warranties on the part of the TCP Parties contained herein as of the Applicable Time and the

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Closing Date to the accuracy of the statements of the TCP Parties made in any certificates pursuant to the provisions hereof, to the performance by the TCP Parties of their respective obligations hereunder and to the following additional conditions:

(a)           The Final Prospectus, or any supplement thereto, will have been filed in the manner and within the time period required by Rule 424(b), and any other material required to be filed by the Partnership pursuant to Rule 433(d), shall have been filed with the Commission within the applicable time periods prescribed for such filings by Rule 433; and no stop order suspending the effectiveness of the Registration Statement or any notice that would prevent its use shall have been issued and no proceedings for that purpose shall have been instituted or threatened.

(b)           All corporate or partnership proceedings and other legal matters incident to the authorization, form and validity of this Agreement, the Notes, the Registration Statement, the Pricing Disclosure Package and the Final Prospectus, and all other legal matters relating to this Agreement and the transactions contemplated hereby shall be reasonably satisfactory in all material respects to counsel for the Underwriters, and the Partnership shall have furnished to such counsel all documents and information that they may reasonably request to enable them to pass upon such matters.

(c)           The Partnership shall have requested and caused Orrick, Herrington & Sutcliffe LLP, counsel for the Partnership, to have furnished to the Underwriters their written opinion, subject to reasonable and customary qualifications, dated the Closing Date and addressed to the Underwriters in form and substance satisfactory to the Underwriters, substantially to the effect that:

(i)            Each of the Partnership Entities, Bison, Great Lakes, GTN and North Baja has been duly formed and is validly existing in good standing as a corporation, limited partnership or limited liability company under the DGCL, the DRULPA or the Delaware LLC Act, as the case may be, with full corporate, partnership or limited liability company power and authority, as the case may be, to own or lease its properties and to conduct the businesses in which it is engaged, in each case in all material respects as described in the Pricing Disclosure Package and the Final Prospectus.  Each of the Partnership Entities is duly registered or qualified as a foreign corporation or limited partnership, as the case may be, for the transaction of business and is in good standing under the laws of the jurisdictions set forth on Exhibit A to this Agreement.

(ii)           The General Partner has full corporate power and authority to act as the general partner of the Partnership and each of the Intermediate Partnerships, in each case in all material respects as described in the Pricing Disclosure Package and the Final Prospectus.

(iii)          Each of the Intermediate Partnerships has full partnership power and authority to act as the general partner of each of Great Lakes, NBPC or Tuscarora, as applicable, in each case in all material respects as described in the Pricing Disclosure Package and the Final Prospectus.

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(iv)          The General Partner is the sole general partner of the Partnership and each of the Intermediate Partnerships with a 1.0% general partner interest in the Partnership and a 1.0101% general partner interest in each of the Intermediate Partnerships; such general partner interests have been duly authorized and validly issued in accordance with the Partnership Agreement and the Intermediate Partnership Agreements; and the General Partner owns such general partner interests free and clear of all liens, encumbrances, security interests, charges or claims (A) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming the General Partner as debtor is on file in the office of the Secretary of State of the State of Delaware as of a recent date or (B) otherwise known to such counsel, without independent investigation, other than those created by or arising under the DRULPA.

(v)           The Partnership owns a 98.9899% limited partner interest in each of the Intermediate Partnerships; such limited partner interests have been duly authorized and validly issued in accordance with the applicable Intermediate Partnership Agreement and are fully paid (to the extent required under the applicable Intermediate Partnership Agreement) and nonassessable (except as such nonassessability ay be affected by Section 17-607 of the DRULPA); and the Partnership owns such limited partner interests free and clear of all liens, encumbrances, security interests, charges or claims (A) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming the Partnership as debtor is on file in the office of the Secretary of State of the State of Delaware as of a recent date or (B) otherwise known to such counsel, without independent investigation, other than those created by or arising under the DRULPA.

(vi)          TCGL Intermediate Partnership owns a 46.45% general partner interest in Great Lakes; such general partner interest has been duly authorized and validly issued in accordance with the Great Lakes Partnership Agreement; and TCP Intermediate Partnership owns such general partner interest free and clear of all liens, encumbrances, security interests, charges or claims (A) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming TCP Intermediate Partnership as debtor is on file in the office of the Secretary of State of the State of Delaware as of a recent date or (B) otherwise known to such counsel, without independent investigation, other than those created by or arising under the DRULPA.

(vii)         TCP Intermediate Partnership owns a 25% membership interest in Bison; such membership interest has been duly authorized and validly issued in accordance with the Bison LLC Agreement; and TCP Intermediate Partnership owns such membership interest free and clear of all liens, encumbrances, security interests, charges or claims (A) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming TCP Intermediate Partnership as debtor is on file in the office of the Secretary of State of the State of Delaware as of a recent date or (B) otherwise known to such

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counsel, without independent investigation, other than those created by or arising under the Delaware LLC Act.

(viii)        TCP Intermediate Partnership owns a 25% membership interest in GTN; such membership interest has been duly authorized and validly issued in accordance with the GTN LLC Agreement; and TCP Intermediate Partnership owns such membership interest free and clear of all liens, encumbrances, security interests, charges or claims (A) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming TCP Intermediate Partnership as debtor is on file in the office of the Secretary of State of the State of Delaware as of a recent date or (B) otherwise known to such counsel, without independent investigation, other than those created by or arising under the Delaware LLC Act.

(ix)           TCP Intermediate Partnership owns its general partner interest in NBPC free and clear of all liens, encumbrances, security interests, charges or claims (A) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming TCP Intermediate Partnership as debtor is on file in the office of the Secretary of State of the State of Delaware as of a recent date or (B) otherwise known to such counsel, without independent investigation, other than those created by or arising under the Texas Revised Partnership Act.

(x)            TCP Intermediate Partnership owns a 100% membership interest in North Baja; such membership interest has been duly authorized and validly issued in accordance with the North Baja LLC Agreement; and TCP Intermediate Partnership owns such membership interest free and clear of all liens, encumbrances, security interests, charges or claims (A) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming TCP Intermediate Partnership as debtor is on file in the office of the Secretary of State of the State of Delaware as of a recent date or (B) otherwise known to such counsel, without independent investigation, other than those created by or arising under the Delaware LLC Act.

(xi)           TCT Intermediate Partnership owns its general partner interest in Tuscarora free and clear of all liens, encumbrances, security interests, charges or claims (A) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming TCT Intermediate Partnership as debtor is on file in the office of the Secretary of State of the State of Delaware as of a recent date or (B) otherwise known to such counsel, without independent investigation, other than those created by or arising under Nevada law.

(xii)          To such counsel’s knowledge, neither the filing of the Registration Statement nor the offering or sale of the Notes by the Partnership as contemplated by this Agreement gives rise to any rights for or relating to the registration of any Notes or other securities of the Partnership, except such rights as have been waived or satisfied.

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(xiii)         The Indenture has been duly qualified under the Trust Indenture Act.

(xiv)        This Agreement has been duly authorized, executed and delivered by each of the TCP Parties.

(xv)         The Base Indenture and the Supplemental Indenture thereto have been duly authorized, executed and delivered by the Partnership, and the Indenture is a valid and legally binding agreement of the Partnership, enforceable against the Partnership in accordance with its terms, except as enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity.

(xvi)        The Notes are in the form contemplated by the Indenture.  The Notes have been duly authorized and, when delivered to and paid for by the Underwriters, will have been duly executed by the Partnership in accordance with the provisions of the Indenture.  The Notes, when authenticated, issued and delivered in the manner provided for in the Indenture and delivered against payment of the purchase price for the Notes as provided in this Agreement, will constitute valid and legally binding obligations of the Partnership enforceable against the Partnership in accordance with its terms, except as enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity.

(xvii)       The Partnership Agreement and the Intermediate Partnership Agreements have been duly authorized, executed and delivered by the General Partner and are valid and legally binding agreements of the General Partner, enforceable against the General Partner in accordance with its terms; provided, that, with respect to each such agreement, the enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and, provided further, that the indemnity, contribution and exoneration provisions contained in any such agreements may be limited by applicable laws and public policy.

(xviii)      The Great Lakes Partnership Agreement has been duly authorized, executed and delivered by TCGL Intermediate Partnership and is a valid and legally binding agreement of TCGL Intermediate Partnership, enforceable against TCGL Intermediate Partnership in accordance with its terms; provided, that the enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and,

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provided further, that the indemnity, contribution and exoneration provisions contained in such agreement may be limited by applicable laws and public policy.

(xix)         The Bison LLC Agreement is a valid and legally binding agreement of TCP Intermediate Partnership, enforceable against TCP Intermediate Partnership in accordance with its terms; provided, that the enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and, provided further, that the indemnity, contribution and exoneration provisions contained in such agreement may be limited by applicable laws and public policy.

(xx)          The GTN LLC Agreement is a valid and legally binding agreement of TCP Intermediate Partnership, enforceable against TCP Intermediate Partnership in accordance with its terms; provided, that the enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and, provided further, that the indemnity, contribution and exoneration provisions contained in such agreement may be limited by applicable laws and public policy.

(xxi)         The North Baja LLC Agreement is a valid and legally binding agreement of TCP Intermediate Partnership, enforceable against TCP Intermediate Partnership in accordance with its terms; provided, that the enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and, provided further, that the indemnity, contribution and exoneration provisions contained in such agreement may be limited by applicable laws and public policy.

(xxii)        None of the issuance, offering and sale by the Partnership of the Notes, the execution, delivery and performance of this Agreement by the TCP Parties, or the consummation of the transactions contemplated hereby or thereby (A) constitutes or will constitute a violation of the Organizational Documents of the Partnership Entities, (B) constitutes or will constitute a breach or violation of, or a default under (or an event that, with notice or lapse of time or both, would constitute such a default), any agreement filed or incorporated by reference as an exhibit to any Incorporated Document (including any amendment or supplement thereto), (C) violates or will violate any federal or Delaware statute, law or regulation, or (D) results or will result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of any of the Partnership Entities, which conflicts, breaches, violations, defaults or liens, in the case of clauses (B), (C) or (D), would, individually or in the aggregate, have a Material

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Adverse Effect or would materially impair the ability of any of the TCP Parties to perform their obligations under this Agreement.

(xxiii)       No permit, consent, approval, authorization, order, registration, filing or qualification of or with any Delaware or federal court, governmental agency or body having jurisdiction over any of the Partnership Entities or any of their respective properties is required in connection with the transactions contemplated herein, except such as have been obtained under the Act and such as may be required under state securities or “Blue Sky” laws in connection with the purchase and distribution of the Notes by the Underwriters in the manner contemplated in this Agreement and in the Final Prospectus.

(xxiv)       The statements in the Preliminary Prospectus, the Pricing Disclosure Package and the Final Prospectus under the captions “Description of Notes,” “Description of Debt Securities” and “Certain United States Federal Income Tax Considerations” as they constitute descriptions of agreements, fairly describe in all material respects the portions of the agreements addressed thereby (except for the description of subordinated debt securities and the subordinated indenture, as to which such counsel need not express any opinion), and insofar as they purport to constitute summaries of law or legal conclusions, fairly describe in all material respects the portions of the statutes and regulations addressed thereby, and the Notes conform in all material respects to the description thereof contained in the Preliminary Prospectus and the Final Prospectus.

(xxv)        The Registration Statement is an “automatic shelf registration statement” (as defined in Rule 405) that has been filed with the Commission not earlier than three years prior to the date of such opinion; any required filing of the Preliminary Prospectus and the Final Prospectus, and any supplements thereto, pursuant to Rule 424(b) has been made in the manner and within the time period required by Rule 424(b); to the knowledge of such counsel, no stop order suspending the effectiveness of the Registration Statement or any notice that would prevent its use has been issued, no proceedings for that purpose have been instituted or threatened.

(xxvi)       The Registration Statement and the Final Prospectus (including any amendment or supplement thereto) (except for the financial statements and the notes and the schedules thereto, and the other financial and statistical information included therein, as to which such counsel need not express any opinion) appear on their face to comply as to form in all material respects with the applicable requirements of the Act and the rules and regulations promulgated thereunder.

(xxvii)      To the knowledge of such counsel, there is no pending or threatened action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Partnership Entities or any of their subsidiaries or their property of a character required to be disclosed in the Registration Statement or the Final Prospectus which is not so disclosed in the

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Pricing Disclosure Package and the Final Prospectus, and there is no franchise, contract or other document of a character required to be described in the Registration Statement or the Final Prospectus, or to be filed as an exhibit thereto, which is not described or filed as required.

(xxviii)     None of the Partnership Entities is and, after giving effect to the offering and sale of the Notes and the application of the proceeds thereof as described in the Preliminary Prospectus and the Final Prospectus, neither will be, an “investment company” as defined in the Investment Company Act of 1940, as amended.

In addition, such counsel shall state that they have participated in conferences with officers and other representatives of the Partnership Entities and the independent public accountants of the Partnership and your representatives, at which the contents of the Registration Statement, the Final Prospectus and the Pricing Disclosure Package and related matters were discussed, and although such counsel has not independently verified, is not passing on, and is not assuming any responsibility for the accuracy, completeness or fairness of the statements contained in, the Registration Statement, the Final Prospectus and the Pricing Disclosure Package (except to the extent specified in the foregoing opinion), nothing has come to such counsel’s attention which would lead it to believe that: (A) any part of the Registration Statement, as of the date on which such part became effective and as of the date of this Agreement, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading, (B)  the Final Prospectus, as of its issue date and the Closing Date, contained or contains any untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading or (C) the Pricing Disclosure Package, as of the Applicable Time, contained any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of circumstances under which they were made, not misleading (other than (i) the financial statements included or incorporated by reference therein, including the notes and schedules thereto and the auditors’ reports thereon, (ii) the other financial and statistical information derived from the financial statements included or incorporated by reference therein and (iii) the Statement of Eligibility of the Trustee on Form T-1, as to which such counsel need not comment).

In rendering such opinion, such counsel may (A) rely in respect of matters of fact upon statements and representations of officers and employees of the TCP Parties, to the extent they deem proper, and upon information obtained from public officials, (B) assume that all documents submitted to them as originals are authentic, that all copies submitted to them conform to the originals thereof, and that the signatures on all documents examined by them are genuine, (C) state that their opinion is limited to federal laws, the DRULPA, the DGCL and the Delaware LLC Act, (D) with respect to the opinions expressed in paragraph (i)

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above as to the due qualification or registration as a foreign limited partnership or corporation, as the case may be, of each the Partnership Entities, state that such opinions are based on certificates of foreign qualification or registration provided by the Secretary of State of the States listed on Exhibit B (each of which shall be dated as of a date not more than fourteen days prior to the Closing Date and shall be provided to the Underwriters) and (E) state that they express no opinion with respect to state or local taxes or tax statutes to which any of the limited partners of the Partnership or any of the Partnership Entities may be subject.

(d)           The Partnership shall have requested and caused Kristine Delkus, in-house counsel for the Partnership, to have furnished to the Underwriters her written opinion, subject to reasonable and customary qualifications, dated the Closing Date and addressed to the Underwriters, substantially to the effect that:

(i)            The statements in the Incorporated Documents under the captions “Business—Overview” and “Business—Regulatory Environment” as they constitute descriptions of agreements, fairly describe in all material respects the portions of the agreements addressed thereby, and insofar as they purport to constitute summaries of law or legal conclusions, fairly describe in all material respects the portions of the statutes and regulations addressed thereby.

(ii)           None of the offering and sale by the Partnership of the Notes, the execution, delivery and performance of this Agreement by the TCP Parties, or the consummation of the transactions contemplated thereby (A) violates or will violate any order, judgment, decree or injunction of any court or governmental agency or body known to such counsel directed to any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora or any of their properties in a proceeding to which any of them or their property is a party or (B) constitutes or will constitute a breach or violation of, or a default under (or an event that, with notice or lapse of time or both, would constitute such a default), any agreement, lease or instrument known to such counsel (excluding any agreement filed or incorporated by reference as an exhibit to any Incorporated Document (including any amendment or supplement thereto) as to which such counsel need not express any opinion) to which any of the Partnership Entities, Bison, Great Lakes, GTN, NBPC, North Baja or Tuscarora is a party, which breaches, violations or defaults, in the case of clauses (A) or (B), would, individually or in the aggregate, have a Material Adverse Effect or would materially impair the ability of any of the TCP Parties to perform their obligations under this Agreement.

(iii)          To the knowledge of such counsel, except as disclosed in the Pricing Disclosure Package and the Final Prospectus, there is no pending or threatened action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Partnership Entities or any of their subsidiaries or their property which, if determined adversely to any such party, would, individually or the aggregate, result in a Material Adverse Effect.

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(e)           The Partnership shall have requested and caused Lisa P. Wang, Texas in-house counsel for the Partnership, to have furnished to the Underwriters her written opinion, subject to reasonable and customary qualifications, dated the Closing Date and addressed to the Underwriters, substantially to the effect that:

(i)            NBPC is validly existing under the laws of the State of Texas with full partnership power and authority to own or lease its properties and to conduct its business in which it is engaged, in each case in all material respects as described in the Pricing Disclosure Package and the Final Prospectus.

(ii)           TCP Intermediate Partnership owns a 50% general partner interest in NBPC; such general partner interest has been duly authorized and validly issued in accordance with the NBPC Partnership Agreement.

(iii)          The NBPC Partnership Agreement has been duly authorized, executed and delivered by TCP Intermediate Partnership and is a valid and legally binding agreement of TCP Intermediate Partnership, enforceable against TCP Intermediate Partnership in accordance with its terms; provided, that the enforceability thereof may be limited by (A) applicable bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and (B) public policy, applicable law relating to fiduciary duties and indemnification and contribution and an implied covenant of good faith and fair dealing.

(f)            The Underwriters shall have received from Baker Botts L.L.P., counsel for the Underwriters, such opinion or opinions, dated the Closing Date and addressed to the Underwriters, with respect to the sale of the Notes, the Registration Statement, the Pricing Disclosure Package, the Final Prospectus (together with any supplement thereto) and other related matters as the Underwriters may reasonably require, and the Partnership shall have furnished to such counsel such documents as they reasonably request for the purpose of enabling them to pass upon such matters.

(g)           The Partnership shall have furnished to the Representatives a certificate reasonably satisfactory to them, signed on behalf of the Partnership by the Chairman of the Board or the President and the principal financial or accounting officer of the General Partner, dated the Closing Date, to the effect that the signers of such certificate have carefully examined the Registration Statement, the Final Prospectus, the Pricing Disclosure Package, any supplements or amendments thereto and this Agreement and that:

(i)            the representations and warranties of the TCP Parties in this Agreement are true and correct on and as of the Closing Date with the same effect as if made on the Closing Date and the TCP Parties have complied with all the agreements and satisfied all the conditions on its part to be performed or satisfied at or prior to the Closing Date;

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(ii)           no stop order suspending the effectiveness of the Registration Statement or any notice that would prevent its use has been issued and no proceedings for that purpose have been instituted or, to such person’s knowledge, threatened;

(iii)          since the date of the most recent financial statements included or incorporated by reference in the Final Prospectus (exclusive of any supplement thereto), there has been no material adverse effect on the condition (financial or otherwise), prospects, earnings, business or properties of the Partnership Entities and their subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business, except as set forth in or contemplated in the Pricing Disclosure Package and the Final Prospectus (exclusive of any supplement thereto); and

(iv)          such other matters as the Underwriters may reasonably request.

(h)           At the time of the execution of this Agreement, the Underwriters shall have received from KPMG LLP a letter or letters with respect to each of the Partnership, Great Lakes, NBPC, GTN and Bison, in form and substance satisfactory to the Representatives, addressed to the Representatives and dated the date hereof, each (i) confirming that they are an independent registered public accounting firm within the meaning of the Act and are in compliance with the applicable rules and regulations thereunder adopted by the Commission and the Public Accounting Oversight Board (“PCAOB”), and (ii) stating that, as of the date hereof (or, with respect to matters involving changes or developments since the respective dates as of which specified financial information is given in the Pricing Disclosure Package and the Prospectus, as of a date not more than three days prior to the date hereof), the conclusions and findings of such firm with respect to the financial information and other matters ordinarily covered by accountants’ “comfort letters” to underwriters in connection with registered public offerings.

(i)            With respect to the letter or letters of KPMG LLP referred to in the preceding paragraph and delivered to the Underwriters concurrently with the execution of this Agreement (the “initial letters”), such accounting firm shall have furnished to the Underwriters a letter or letters (the “bring-down letters”) of KPMG LLP, addressed to the Underwriters and dated the Closing Date (i) confirming that they are an independent registered public accounting firm within the meaning of the Act and are in compliance with the applicable rules and regulations thereunder adopted by the Commission and the PCAOB, (ii) stating that, as of the date of such bring-down letter (or, with respect to matters involving changes or developments since the respective dates as of which specified financial information is given in the Prospectus, as of a date not more than three days prior to the date of such bring-down letter), the conclusions and findings of such firm with respect to the financial information and other matters covered by the initial letters and (iii) confirming in all material respects the conclusions and findings set forth in the initial letters.

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(j)            Subsequent to the Applicable Time or, if earlier, the dates as of which information is given in the Registration Statement (exclusive of any amendment thereof), the Pricing Disclosure Package and the Final Prospectus (exclusive of any supplement thereto), there shall not have been (i) any change or decrease specified in the letter or letters referred to in paragraphs (h) and (i) of this Section 6 or (ii) any change, or any development involving, individually or in the aggregate, a prospective change, in or affecting the general affairs, condition (financial or other), business, prospects, assets or results of operations of the Partnership and its subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business, except as set forth in or contemplated in the Pricing Disclosure Package and the Final Prospectus the effect of which, in any case referred to in clause (i) or (ii) above, is, in the sole judgment of the Representatives, so material and adverse as to make it impractical or inadvisable to proceed with the offering or delivery of the Notes as contemplated by the Registration Statement, the Pricing Disclosure Package and the Final Prospectus.

(k)           Subsequent to the Applicable Time, there shall not have been any decrease in the rating of any of the Partnership’s debt securities by any “nationally recognized statistical rating organization” (as defined for purposes of Rule 15c3-1(c)(2)(vi)(F) under the Exchange Act) or any notice given of any intended or potential decrease in any such rating or of a possible change in any such rating that does not indicate the direction of the possible change.

(l)            The Partnership and the Trustee shall have executed and delivered the Indenture, and the Partnership shall have executed and delivered the Notes.

(m)          Prior to the Closing Date, the TCP Parties shall have furnished to the Representatives such further information, certificates and documents as the Representatives may reasonably request.

If any of the conditions specified in this Section 6 shall not have been fulfilled when and as provided in this Agreement, or if any of the opinions and certificates mentioned above or elsewhere in this Agreement shall not be reasonably satisfactory in form and substance to the Representatives and counsel for the Underwriters, this Agreement and all obligations of the Underwriters hereunder may be canceled at, or at any time prior to, the Closing Date by the Representatives.  Notice of such cancellation shall be given to the Partnership in writing or by telephone or facsimile confirmed in writing.

7.             Reimbursement of Underwriters’ Expenses.  If the sale of the Notes provided for herein is not consummated because any condition to the obligations of the Underwriters set forth in Section 6 hereof is not satisfied, because of any termination pursuant to Section 10 hereof or because of any refusal, inability or failure on the part of the TCP Parties to perform any agreement herein or comply with any provision hereof other than by reason of a default by any of the Underwriters, the TCP Parties will reimburse the Underwriters severally through the Representatives on demand for all out-of-pocket expenses (including reasonable fees and disbursements of counsel) that shall have been incurred by them in connection with the proposed purchase and sale of the Notes.

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8.             Indemnification and Contribution.

(a)           Each of the TCP Parties, jointly and severally, agree to indemnify and hold harmless each Underwriter, the directors, officers, employees and agents of each Underwriter and each person who controls any Underwriter within the meaning of either the Act or the Exchange Act against any and all losses, claims, damages or liabilities, joint or several, to which they or any of them may become subject under the Act, the Exchange Act or other federal or state statutory law or regulation, at common law or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, any Preliminary Prospectus, any Permitted Free Writing Prospectus, the Final Prospectus, any Issuer Free Writing Prospectus or any “road show” (as defined in Rule 433) not constituting an Issuer Free Writing Prospectus (a “Non-Prospectus Road Show”), or in any amendment thereof or supplement thereto, (ii) the omission or alleged omission to state in the Registration Statement a material fact required to be stated therein or necessary to make the statements therein not misleading or (iii) the omission or alleged omission to state in any Preliminary Prospectus, any Permitted Free Writing Prospectus, the Final Prospectus, any Issuer Free Writing Prospectus or any Non-Prospectus Road Show a material fact necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, and agrees to reimburse each such indemnified party, as incurred, for any legal or other expenses reasonably incurred by them in connection with investigating or defending any such loss, claim, damage, liability or action; provided, however, that each of the TCP Parties will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon any such untrue statement or alleged untrue statement or omission or alleged omission made therein in reliance upon and in conformity with written information furnished to the Partnership by or on behalf of any Underwriter through the Representatives specifically for inclusion therein, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in Section 8(b) hereof.  This indemnity agreement will be in addition to any liability which the TCP Parties may otherwise have.

(b)           Each Underwriter severally and not jointly agrees to indemnify and hold harmless the TCP Parties, each of their respective directors, each of its officers who signs the Registration Statement, and each person who controls the TCP Parties within the meaning of either the Act or the Exchange Act, to the same extent as the foregoing indemnity to each Underwriter, but only with reference to written information relating to such Underwriter furnished to the Partnership by or on behalf of such Underwriter through the Representatives specifically for inclusion in the documents referred to in the foregoing indemnity, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in this Section 8(b).  This indemnity agreement will be in addition to any liability which any Underwriter may otherwise have.  The TCP Parties acknowledge that the statements set forth in the last paragraph of the cover page regarding delivery of the Notes and, under the heading “Underwriting,” (i) the list of Underwriters and their respective participation in the sale of the Notes, (ii) the paragraph under “Underwriting—Commissions and Discounts” and (iii) the paragraph under “Underwriting—Stabilization

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and Short Positions” in any Preliminary Prospectus, the Final Prospectus and any Issuer Free Writing Prospectus constitute the only information furnished in writing by or on behalf of the several Underwriters for inclusion in any Preliminary Prospectus, the Final Prospectus or any Issuer Free Writing Prospectus, or in any amendment or supplement thereto.

(c)           Promptly after receipt by an indemnified party under this Section 8 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against the indemnifying party under this Section 8, notify the indemnifying party in writing of the commencement thereof; but the failure so to notify the indemnifying party (i) will not relieve it from liability under paragraph (a) or (b) above unless and to the extent it did not otherwise learn of such action and such failure results in the forfeiture by the indemnifying party of substantial rights and defenses and (ii) will not, in any event, relieve the indemnifying party from any obligations to any indemnified party other than the indemnification obligation provided in paragraph (a) or (b) above.  The indemnifying party shall be entitled to appoint counsel of the indemnifying party’s choice at the indemnifying party’s expense to represent the indemnified party in any action for which indemnification is sought (in which case the indemnifying party shall not thereafter be responsible for the fees and expenses of any separate counsel retained by the indemnified party or parties except as set forth below); provided, however, that such counsel shall be satisfactory to the indemnified party.  Notwithstanding the indemnifying party’s election to appoint counsel to represent the indemnified party in an action, the indemnified party shall have the right to employ separate counsel (including local counsel), and the indemnifying party shall bear the reasonable fees, costs and expenses of such separate counsel if (i) the use of counsel chosen by the indemnifying party to represent the indemnified party would present such counsel with a conflict of interest, (ii) the actual or potential defendants in, or targets of, any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that there may be legal defenses available to it and/or other indemnified parties which are different from or additional to those available to the indemnifying party, (iii) the indemnifying party shall not have employed counsel satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of the institution of such action or (iv) the indemnifying party shall authorize the indemnified party to employ separate counsel at the expense of the indemnifying party.  An indemnifying party will not, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any pending or threatened claim, action, suit or proceeding in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified parties are actual or potential parties to such claim or action) unless such settlement, compromise or consent (i) includes an unconditional release of each indemnified party from all liability arising out of such claim, action, suit or proceeding and (ii) does not include a statement as to or an admission of fault, culpability or a failure to act, by or on behalf of any indemnified party.

(d)           In the event that the indemnity provided in paragraph (a) or (b) of this Section 8 is unavailable to or insufficient to hold harmless an indemnified party for any reason, the TCP Parties, jointly and severally, and the Underwriters severally agree to

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contribute to the aggregate losses, claims, damages and liabilities (including legal or other expenses reasonably incurred in connection with investigating or defending same) (collectively “Losses”) to which the TCP Parties and one or more of the Underwriters may be subject in such proportion as is appropriate to reflect the relative benefits received by the TCP Parties on the one hand and by the Underwriters on the other from the offering of the Notes; provided, however, that in no case shall any Underwriter (except as may be provided in any agreement among underwriters relating to the offering of the Notes) be responsible for any amount in excess of the underwriting discount or commission applicable to the Notes purchased by such Underwriter hereunder. If the allocation provided by the immediately preceding sentence is unavailable for any reason, the TCP Parties, jointly and severally, and the Underwriters severally shall contribute in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the TCP Parties on the one hand and of the Underwriters on the other in connection with the statements or omissions which resulted in such Losses as well as any other relevant equitable considerations.  Benefits received by the TCP Parties shall be deemed to be equal to the total net proceeds from the offering (before deducting expenses) received by the Partnership, and benefits received by the Underwriters shall be deemed to be equal to the total underwriting discounts and commissions, in each case as set forth on the cover page of the Final Prospectus.  Relative fault shall be determined by reference to, among other things, whether any untrue or any alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information provided by the TCP Parties on the one hand or the Underwriters on the other, the intent of the parties and their relative knowledge, access to information and opportunity to correct or prevent such untrue statement or omission.  The TCP Parties and the Underwriters agree that it would not be just and equitable if contribution were determined by pro rata allocation or any other method of allocation which does not take account of the equitable considerations referred to above.  Notwithstanding the provisions of this paragraph (d), no person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation.  For purposes of this Section 8, each person who controls an Underwriter within the meaning of either the Act or the Exchange Act and each director, officer, employee and agent of an Underwriter shall have the same rights to contribution as such Underwriter, and each person who controls any of the TCP Parties within the meaning of either the Act or the Exchange Act, each officer of the TCP Parties who shall have signed the Registration Statement and each director of the TCP Parties shall have the same rights to contribution as the TCP Parties, subject in each case to the applicable terms and conditions of this paragraph (d).

9.             Default by an Underwriter.  If any one or more Underwriters shall fail to purchase and pay for any of the Notes agreed to be purchased by such Underwriter or Underwriters hereunder and such failure to purchase shall constitute a default in the performance of its or their obligations under this Agreement, the remaining Underwriters shall be obligated severally to take up and pay for (in the respective proportions which the principal amount of Notes set forth opposite their names in Schedule 1 hereto bears to the aggregate principal amount of Notes set forth opposite the names of all the remaining Underwriters) the Notes which the defaulting Underwriter or Underwriters agreed but failed to purchase; provided, however, that in the event that the aggregate principal amount of Notes which the defaulting Underwriter or

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Underwriters agreed but failed to purchase shall exceed 10% of the aggregate principal amount of Notes set forth in Schedule 1 hereto, the remaining Underwriters shall have the right to purchase all, but shall not be under any obligation to purchase any, of the Notes, and if such nondefaulting Underwriters do not purchase all the Notes, this Agreement will terminate without liability to any nondefaulting Underwriter or the TCP Parties.  In the event of a default by any Underwriter as set forth in this Section 9, the Closing Date shall be postponed for such period, not exceeding five Business Days, as the Representatives shall determine in order that the required changes in the Pricing Disclosure Package and the Final Prospectus or in any other documents or arrangements may be effected.  Nothing contained in this Agreement shall relieve any defaulting Underwriter of its liability, if any, to the TCP Parties and any nondefaulting Underwriter for damages occasioned by its default hereunder.

10.           Termination.  This Agreement shall be subject to termination in the absolute discretion of the Representatives, by notice given to the Partnership prior to delivery of and payment for the Notes, if at any time prior to such time (i) trading in the Partnership’s Common Units shall have been suspended by the Commission or the Nasdaq Stock Market or trading in securities generally on the New York Stock Exchange or the Nasdaq Stock Market shall have been suspended or limited or minimum prices shall have been established on the New York Stock Exchange or the Nasdaq Stock Market, (ii) a banking moratorium shall have been declared either by Federal or New York State authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States shall have occurred or (iii) there shall have occurred any outbreak or escalation of hostilities, declaration by the United States of a national emergency or war, or other calamity or crisis the effect of which on financial markets is such as to make it, in the sole judgment of the Representatives, impractical or inadvisable to proceed with the offering or delivery of the Notes as contemplated by the Final Prospectus (exclusive of any supplement thereto).

11.           Representations and Indemnities to Survive.  The respective agreements, representations, warranties, indemnities and other statements of the TCP Parties or their respective officers and of the Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation made by or on behalf of any Underwriter, the TCP Parties or any of their respective officers, directors, employees, agents or controlling persons referred to in Section 8 hereof, and will survive delivery of and payment for the Notes.  The provisions of Sections 7 and 8 hereof shall survive the termination or cancellation of this Agreement.

12.           Notices.  All communications hereunder will be in writing and effective only on receipt, and, if sent to the Partnership Parties, will be mailed or delivered to TC PipeLines, LP, 13710 FNB Parkway, Omaha, Nebraska 68154; or if sent to the Underwriters, c/o J.P. Morgan Securities LLC, 383 Madison Avenue, New York, NY 10179, Attention High Grade Syndicate Desk—3rd Floor, facsimile no. (212) 834-6081.

13.           Successors.  This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers, directors, employees, agents and controlling persons referred to in Section 8 hereof, and no other person will have any right or obligation hereunder.

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14.           No Fiduciary Duty.  Each of the TCP Parties hereby acknowledges that (a) the purchase and sale of the Notes pursuant to this Agreement is an arm’s-length commercial transaction between the Partnership, on the one hand, and the Underwriters and any affiliate through which it may be acting, on the other, (b) the Underwriters are acting as principal and not as an agent or fiduciary of the Partnership and (c) the Partnership’s engagement of the Underwriters in connection with the offering and the process leading up to the offering is as independent contractors and not in any other capacity. Furthermore, the Partnership agrees that it is solely responsible for making its own judgments in connection with the offering (irrespective of whether any of the Underwriters has advised or is currently advising the Partnership on related or other matters).  The Partnership agrees that it will not claim that the Underwriters have rendered advisory services of any nature or respect, or owe an agency, fiduciary or similar duty to the Partnership, in connection with such transaction or the process leading thereto.

15.           Integration.  This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Partnership and the Underwriters, or any of them, with respect to the subject matter hereof.

16.           Applicable Law.  This Agreement will be governed by and construed in accordance with the laws of the State of New York applicable to contracts made and to be performed within the State of New York.

17.           Venue.  Each of the parties hereto irrevocably (i) agrees that any legal suit, action or proceeding arising out of or based upon this Agreement or the transactions contemplated hereby may be instituted in any court within the Borough of Manhattan of New York City, (ii) waives, to the fullest extent it may effectively do so, any objection which it may now or hereafter have to the laying of venue of any such proceeding and (iii) submits to the exclusive jurisdiction of such courts in any such suit, action or proceeding.

18.           Counterparts.  This Agreement may be signed in one or more counterparts, each of which shall constitute an original and all of which together shall constitute one and the same agreement.

19.           Headings.  The section headings used herein are for convenience only and shall not affect the construction hereof.

20.           Definitions.  The terms which follow, when used in this Agreement, shall have the meanings indicated.

“Act” shall mean the Securities Act of 1933, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Applicable Time” means 4:08 p.m. (New York City time) on June 14, 2011, which the Underwriters have informed the Partnership is a time prior to the time of the first sale of the Notes.

“Base Prospectus” shall mean the base prospectus filed as part of the Registration Statement, in the form in which it has most recently been amended at the Applicable Time.

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“Business Day” shall mean any day other than a Saturday, a Sunday or a legal holiday or a day on which banking institutions or trust companies are authorized or obligated by law to close in New York City.

“Commission” shall mean the Securities and Exchange Commission.

“Effective Date” shall mean any date as of which any part of the Registration Statement relating to the Notes became, or is deemed to have become, effective under the Securities Act in accordance with the Rules and Regulations.

“Exchange Act” shall mean the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Final Prospectus” shall mean the prospectus supplement relating to the Notes and the base prospectus that is part of the registration statement that were first filed pursuant to Rule 424(b) after the Applicable Time.

“Incorporated Documents” shall mean the documents which at the time are incorporated by reference in the Registration Statement, the Base Prospectus, the Final Preliminary Prospectus or the Final Prospectus or any amendment or supplement thereto.

“Issuer Free Writing Prospectus” shall mean each “free writing prospectus” (as defined in Rule 405) prepared by or on behalf of the Partnership or used or referred to by the Partnership in connection with the offering of the Notes.

“Preliminary Prospectus” shall mean the preliminary prospectus supplement relating to the Notes that is filed with the Commission pursuant to Rule 424(b) and used prior to the filing of the Final Prospectus, together with the Base Prospectus.

“Pricing Disclosure Package” shall mean, as of the Applicable Time, the Preliminary Prospectus, together with (A) the Issuer Free Writing Prospectus attached as Schedule 2 hereto and (B) each other Issuer Free Writing Prospectus filed or used by the Partnership on or before the Applicable Time, other than a road show that is an Issuer Free Writing Prospectus under Rule 433.

“Registration Statement” shall mean, collectively, the various parts of the registration statement on Form S-3 (file number 333-166221), including exhibits and financial statements and any information in the prospectus supplement relating to the Notes that is filed with the Commission pursuant to Rule 424(b) and deemed part of such registration statement pursuant to Rule 430B, as amended on each Effective Date and, in the event of any post-effective amendment thereto or any Rule 462(b) Registration Statement becomes effective prior to the Closing Date, shall also mean such registration statement as so amended or such Rule 462(b) Registration Statement, as the case may be.

“Rule 158”, “Rule 163”, “Rule 164”, “Rule 172”, “Rule 405”, “Rule 415”, “Rule 424”, “Rule 430B”, “Rule 433” and “Rule 462” refer to such rules under the Act.

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“Rule 462(b) Registration Statement” shall mean a registration statement and any amendments thereto filed pursuant to Rule 462(b) relating to the offering covered by the registration statement referred to in Section 1(i)(a) hereof.

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If the foregoing is in accordance with your understanding of our agreement, please sign and return to us the enclosed duplicate hereof, whereupon this letter and your acceptance shall represent a binding agreement among the TCP Parties and the several Underwriters.

SCHEDULE 1

SCHEDULE 2

ISSUER FREE WRITING PROSPECTUS

Filed Pursuant to Rule 433

Registration No. 333-166221

June 14, 2011

TC PipeLines, LP

Pricing Term Sheet

$350,000,000 4.65% Senior Notes due 2021

The issuer has filed a registration statement (including a prospectus) with the U.S. Securities and Exchange Commission (SEC) for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering.

You may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling J.P. Morgan Securities LLC collect at 1-212-834-4533 or SunTrust Robinson Humphrey, Inc. toll-free at 1-800-685-4786.

SCHEDULE 3

Permitted Free Writing Prospectuses

The Issuer Free Writing Prospectus attached as Schedule 2 to the Agreement.

Exhibit A

States of Foreign Qualification

TC PipeLines, LP

Nebraska

New York

TC PipeLines GP, Inc.

California

Illinois

Iowa

Minnesota

Montana

Nebraska

Nevada

New York

North Dakota

Oregon

South Dakota

Texas

TC GL Intermediate Limited Partnership

None

TC PipeLines Intermediate Limited Partnership

Illinois

Iowa

Minnesota

Montana

Nebraska

New York

North Dakota

South Dakota

Texas

TC Tuscarora Intermediate Limited Partnership

California

Nevada

Oregon

Bison Pipeline LLC

Montana

Nebraska

North Dakota

Texas

Wyoming

Gas Transmission Northwest LLC

Arizona

Idaho

Oregon

Texas

Washington

Great Lakes Gas Transmission Limited Partnership

Michigan

Minnesota

Wisconsin

North Baja Pipeline, LLC

Arizona

California

Exhibit 4.1

EXECUTION VERSION

TC PIPELINES, LP,

ISSUER

AND

THE BANK OF NEW YORK MELLON

TRUSTEE

INDENTURE

Dated as of June 17, 2011

SENIOR DEBT SECURITIES

TC PipeLines, LP

Reconciliation and Tie Between Trust Indenture Act of 1939, as amended, and Indenture,
dated as of  June 17, 2011

NOTE:  This reconciliation and tie shall not, for any purpose, be deemed to be a part of the Indenture.

*              Deemed included pursuant to Section 318 (c) of the Trust Indenture Act

TABLE OF CONTENTS

i

TABLE OF CONTENTS

(continued)

ii

TABLE OF CONTENTS

(continued)

iii

TABLE OF CONTENTS

(continued)

iv

INDENTURE

Parties:

INDENTURE, dated as of June 17, 2011, between TC PIPELINES, LP, a Delaware limited partnership (herein called the “Partnership”), having its principal office at 13710 FNB Parkway, Suite 300, Omaha, Nebraska  68154-05200 and THE BANK OF NEW YORK MELLON, as trustee (herein called the “Trustee”), a banking corporation organized under the laws of the State of New York.

Recitals of the Partnership:

The Partnership has duly authorized the execution and delivery of this Indenture to provide for the issuance from time to time of its unsecured senior debentures, notes or other evidences of indebtedness (herein called the “Securities”), to be issued in one or more series as in this Indenture provided.

All things necessary to make this Indenture a valid agreement of the Partnership, in accordance with its terms, have been done.

This Indenture is subject to the provisions of the Trust Indenture Act that are required to be a part of this Indenture and, to the extent applicable, shall be governed by such provisions.

NOW, THEREFORE, THIS INDENTURE WITNESSETH:

For and in consideration of the premises and the purchase of the Securities by the Holders thereof, it is mutually covenanted and agreed, for the equal and proportionate benefit of all Holders of the Securities or of any series thereof, as follows:

ARTICLE I
DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

SECTION 101.                     Definitions.

For all purposes of this Indenture, except as otherwise expressly provided or unless the context otherwise requires:

(1)           the terms defined in this Article have the meanings assigned to them in this Article and include the plural as well as the singular;

(2)           all other terms used herein which are defined in the Trust Indenture Act, either directly, or by reference therein or defined by a Commission rule under the Trust Indenture Act, have the meanings assigned to them therein;

(3)           all accounting terms not otherwise defined herein have the meanings assigned to them in accordance with generally accepted accounting principles in the United States, and, except as otherwise herein expressly provided, the term “generally accepted accounting principles” with respect to any computation required or permitted

hereunder shall mean such accounting principles as are generally accepted in the United States at the date of such computation;

(4)           the words “herein,” “hereof” and “hereunder” and other words of similar import refer to this Indenture as a whole and not to any particular Article, Section or other subdivision;

(5)           the words “Article” and “Section” refer to an Article and Section, respectively, of this Indenture; and

(6)           the word “includes” and its derivatives means “includes, but is not limited to” and its corresponding derivative definitions.

Certain terms, used principally in Article VI, are defined in that Article.

“Act,” when used with respect to any Holder, has the meaning specified in Section 105.

“Affiliate” of any specified Person means any other Person directly or indirectly controlling or controlled by or under direct or indirect common control with such specified Person.  For the purposes of this definition, “control” when used with respect to any specified Person means the power to direct the management and policies of such Person, directly or indirectly, whether through the ownership of voting securities, by contract or otherwise, and the terms “controlling” and “controlled” have meanings correlative to the foregoing.

“Authenticating Agent” means any Person authorized by the Trustee to act on behalf of the Trustee to authenticate Securities.

“Banking Day” means, with respect to any city, any date on which commercial banks are open for business in that city.

“Bankruptcy Law” means Title 11, U.S. Code, or any similar federal or state law for the relief of debtors or the protection of creditors.

“Board of Directors” means the board of directors of the General Partner, or the executive or any other committee of that board duly authorized to act in respect thereof.  If the Partnership shall change its form of entity to other than a limited partnership, the references to officers or the Board of Directors of the General Partner shall mean the officers or the Board of Directors (or other comparable governing body), respectively, of the Partnership.

“Board Resolution” means a copy of a resolution certified by the Secretary or an Assistant Secretary of the General Partner, the principal financial officer of the General Partner or any other authorized officer of the General Partner or a person duly authorized by any of them, to have been duly adopted by the Board of Directors and to be in full force and effect on the date of such certification, and delivered to the Trustee.  Where any provision of this Indenture refers to action to be taken pursuant to a Board Resolution (including the establishment of any series of the Securities and the forms and terms thereof), such action may be taken by any committee, officer or employee of the Partnership authorized to take such action by the Board of Directors as evidenced by a Board Resolution.

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“Business Day,” when used with respect to any Place of Payment or other location, means, except as otherwise provided as contemplated by Section 301 with respect to any series of Securities, each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking institutions in that Place of Payment or New York City are authorized or obligated by law, executive order or regulation to close.

“Capital Interests” means any and all shares, interests, participations, rights or other equivalents (however designated) of capital stock, including, without limitation, with respect to partnerships, partnership interests (whether general or limited) and any other interest or participation that confers on a Person the right to receive a share of the profits and losses of, or distributions of assets of, such partnership.

“Commission” means the Securities and Exchange Commission, as from time to time constituted, created under the Exchange Act or, if at any time after the execution of this instrument such Commission is not existing and performing the duties now assigned to it under the Trust Indenture Act, then the body performing such duties at such time.

“Consolidated Net Tangible Assets” means, at any date of determination, the total amount of assets after deducting therefrom (a) all current liabilities (excluding (i) any current liabilities renewable or extendable at the option of the obligor to a time more than 12 months after the time as of which the amount thereof is being computed, and (ii) current maturities of long-term debt), and (b) the value (net of any applicable reserves) of all goodwill, trade names, trademarks, patents, unamortized debt discount and expense and other like intangibles, all as set forth on the consolidated balance sheet of the Partnership and its consolidated Subsidiaries for the Partnership’s most recently completed fiscal quarter, prepared in accordance with GAAP.

“Corporate Trust Office” means the office of the Trustee at which at any particular time its corporate trust business shall be principally administered, and which, at the date hereof is located at The Bank of New York Mellon, 101 Barclay Street, Floor 4-East, New York, New York  10286, Attn: International Corporate Trust (Fax: (212) 815-5915 or (212) 815-5366).

“corporation” includes corporations, associations, limited liability companies, joint-stock companies and business trusts.

“covenant defeasance” has the meaning specified in Section 1303.

“CUSIP” means the Committee on Uniform Securities Identification Procedures.

“Custodian” means any receiver, trustee, assignee, liquidator or similar official under any Bankruptcy Law.

“Debt” means any obligation created or assumed by any Person for the repayment of money borrowed, and any purchase money obligation created or assumed by such Person and any guarantee of the foregoing (without duplication).

“Default” means, with respect to a series of Securities, any event that is, or after notice or lapse of time or both would be, an Event of Default.

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“Defaulted Interest” has the meaning specified in Section 307.

“defeasance” has the meaning specified in Section 1302.

“Definitive Security” means a Security other than a Global Security or a temporary Security.

“Depositary” means, with respect to Securities of any series issuable or issued in whole or in part in the form of one or more Global Securities, a clearing agency registered under the Exchange Act that is designated to act as Depositary for such Securities as contemplated by Section 301, until a successor Depositary shall have become such pursuant to the applicable provisions of this Indenture, and thereafter shall mean or include each Person which is then a Depositary hereunder, and if at any time there is more than one such Person, shall be a collective reference to such Persons.

“Dollar” or “$” means the coin or currency of the United States of America as at the time of payment is legal tender for the payment of public and private debts.

“Event of Default” has the meaning specified in Section 501.

“Exchange Act” means the Securities Exchange Act of 1934, as amended from time to time, and any statute successor thereto.

“Foreign Currency” means a currency used by the government of a country other than the United States of America.

“GAAP” means generally accepted accounting principles in the United States set forth in the opinions and pronouncements of the Accounting Principles Board of the American Institute of Certified Public Accountants and statements and pronouncements of the Financial Accounting Standards Board or in such other statements by such other entity as may be approved by a significant segment of the accounting profession of the United States, as in effect from time to time.

“General Partner” means the person serving as such under the Partnership Agreement, which, on the date hereof, is TC PipeLines GP, Inc., a Delaware corporation.

“Global Security” means a Security in global form that evidences all or part of a series of Securities and is authenticated and delivered to, and registered in the name of, the Depositary for the Securities of such series or its nominee or custodian.

“Hedging Obligation” means, with respect to any Person, the obligations of such Person under interest rate and commodity price swap agreements, interest rate and commodity price cap agreements, interest rate and commodity collar agreements and foreign currency and commodity price exchange agreements, options or futures or other similar agreements or arrangements, in each case designed to protect such Person against fluctuations in interest rates, foreign exchange rates or commodity prices.

“Holder” means a Person in whose name a Security is registered in the Security Register.

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“Indenture” means this instrument as originally executed or as it may from time to time be supplemented or amended by one or more indentures supplemental hereto entered into pursuant to the applicable provisions hereof, including, for all purposes of this instrument, and any such supplemental indenture, the provisions of the Trust Indenture Act that are deemed to be a part of and govern this instrument and any such supplemental indenture, respectively.  The term “Indenture” also shall include the terms of particular series of Securities established as contemplated by Section 301.

“interest,” when used with respect to an Original Issue Discount Security, which by its terms bears interest only after Maturity, means interest payable after Maturity.

“Interest Payment Date,” when used with respect to any Security, means the Stated Maturity of an installment of interest on such Security.

“Issue Date” means, with respect to any series of Debt Securities issued under this Indenture, the date on which Debt Securities of that series are initially issued.

“Lien” means any mortgage, pledge, security interest, charge, lien or other encumbrance of any kind, whether or not filed, recorded and perfected under applicable law.

“mandatory sinking fund payment” has the meaning specified in Section 1201.

“Maturity,” when used with respect to any Security, means the date on which the principal of such Security or an installment of principal becomes due and payable as therein or herein provided, whether at the Stated Maturity or by declaration of acceleration, call for redemption or otherwise.

“Notice of Default” means a written notice of the kind specified in Section 501(3).

“Officers’ Certificate” means a certificate in compliance with Section 103 hereof, if applicable, signed by any two officers of the General Partner (or if the Partnership shall change its form of entity to other than a limited partnership, by Persons or officers, members, agents and the like positions comparable to those of the foregoing nature, as applicable), and delivered to the Trustee.  One of the officers or such other Persons (as applicable) signing an Officers’ Certificate given pursuant to Section 1004 shall be the principal executive, financial or accounting officer of the General Partner (or if the Partnership shall change its form of entity to other than a limited partnership, by Persons or officers, members, agents and the like positions comparable to those of the foregoing nature, as applicable).

“Opinion of Counsel” means a written opinion of counsel, who may be an employee of or counsel for the Partnership, the General Partner or an Affiliate of the General Partner and which opinion shall be reasonably acceptable to the Trustee and, if applicable, shall be in compliance with Section 103 hereof.

“Original Issue Discount Security” means any Security which provides for an amount less than the stated principal amount thereof to be due and payable upon a declaration of acceleration of the Maturity thereof pursuant to Section 502.

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“Outstanding,” when used with respect to Securities, means, as of the date of determination, all Securities theretofore authenticated and delivered under this Indenture, except:

(7)           Securities theretofore canceled by the Trustee or delivered to the Trustee for cancellation;

(8)           Securities for whose payment or redemption money in the necessary amount has been theretofore deposited with the Trustee or any Paying Agent (other than the Partnership) in trust or set aside and segregated in trust by the Partnership (if the Partnership shall act as its own Paying Agent) for the Holders of such Securities; provided, however, that, if such Securities are to be redeemed, notice of such redemption has been duly given pursuant to this Indenture or provision therefor satisfactory to the Trustee has been made;

(9)           Securities which have been paid pursuant to Section 306 or in exchange for or in lieu of which other Securities have been authenticated and delivered pursuant to this Indenture, other than any such Securities in respect of which there shall have been presented to the Trustee proof satisfactory to it that such Securities are held by a bona fide purchaser in whose hands such Securities are valid obligations of the Partnership; and

(10)         Securities, except to the extent provided in Sections 1302 and 1303, with respect to which the Partnership has effected defeasance or covenant defeasance as provided in Article XIII which continues in effect;

provided, however, that in determining whether the Holders of the requisite principal amount of the Outstanding Securities have given any request, demand, authorization, direction, notice, consent or waiver hereunder, (A) the principal amount of an Original Issue Discount Security that shall be deemed to be Outstanding shall be the amount of the principal thereof that would be due and payable as of the date of such determination upon acceleration of the Maturity thereof on such date pursuant to Section 502, (B) the principal amount of a Security denominated in one or more currencies or currency units other than Dollars shall be the Dollar equivalent of such currencies or currency units, determined in the manner provided as contemplated by Section 301 on the date of original issuance of such Security or by Section 115, if not otherwise so provided pursuant to Section 301, of the principal amount (or, in the case of an Original Issue Discount Security, the Dollar equivalent (as so determined) on the date of original issuance of such Security, of the amount determined as provided in clause (A) above) of such Security, and (C) Securities owned by the Partnership or any other obligor upon the Securities or any Affiliate of the Partnership or of such other obligor shall be disregarded and deemed not to be Outstanding, except that, in determining whether the Trustee shall be protected in relying upon any such request, demand, authorization, direction, notice, consent or waiver, only Securities which the Trustee knows to be so owned shall be so disregarded. Securities so owned as described in clause (C) of the immediately preceding sentence which have been pledged in good faith may be regarded as Outstanding if the pledgee establishes to the satisfaction of the Trustee the pledgee’s right so to act with respect to such Securities and that the pledgee is not the Partnership or any other obligor upon the Securities or any Affiliate of the Partnership or of such other obligor.

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“Pari Passu Debt” means any Debt of the Partnership, whether outstanding on the Issue Date or thereafter created, incurred or assumed, unless, in the case of any particular Debt, the instrument creating or evidencing the same or pursuant to which the same is outstanding expressly provides that such Debt shall be subordinated in right of payment to the Securities.

“Partnership” means the Person named as the “Partnership” in the first paragraph of this instrument until a successor Person shall have become such pursuant to the applicable provisions of this Indenture, and thereafter “Partnership” shall mean such successor Person.

“Partnership Agreement” means the Agreement of Limited Partnership of the Partnership, including all amendments thereto, as in effect from time to time.

“Partnership Request” or “Partnership Order” means a written request or order delivered to the Trustee and signed in the name of the Partnership by any two officers of the General Partner, or if the Partnership shall change its form of entity to other than a limited partnership, by Persons or officers, members, agents and the like positions comparable to those of the foregoing nature, as applicable.

“Paying Agent” means any Person authorized by the Partnership to pay the principal of and any premium or interest on any Securities on behalf of the Partnership.

“Periodic Offering” means an offering of Securities of a series from time to time, the specific terms of which Securities, including, without limitation, the rate or rates of interest or formula for determining the rate or rates of interest thereon, if any, the Stated Maturity or Stated Maturities thereof, the original issue date or dates thereof, the redemption provisions, if any, with respect thereto, and any other terms specified as contemplated by Section 301 with respect thereto, are to be determined by the Partnership upon the issuance of such Securities.

“Permitted Liens” means, with respect to any Person:

(1)           Liens upon rights-of-way for pipeline purposes;

(2)           any statutory or governmental Lien or Lien arising by operation of law, or any mechanics’, repairmen’s, materialmen’s, suppliers’, carriers’, landlords’, warehousemen’s or similar Lien incurred in the ordinary course of business which is not yet due or which is being contested in good faith by appropriate proceedings and any undetermined Lien which is incidental to construction, development, improvement or repair;

(3)           the right reserved to, or vested in, any municipality or public authority by the terms of any right, power, franchise, grant, license, permit or by any provision of law, to purchase or recapture or to designate a purchaser of, any property;

(4)           Liens of taxes and assessments which are (A) for the then current year, (B) not at the time delinquent, or (C) delinquent but the validity of which is being contested at the time in good faith by the Partnership or any of its Subsidiaries;

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(5)           Liens arising under, or to secure performance of, leases, other than capital leases;

(6)           any Lien upon, or deposits of, any assets in favor of any surety company or clerk of court for the purpose of obtaining indemnity or stay of judicial proceedings;

(7)           any Lien upon property or assets acquired or sold by the Partnership or any of its Subsidiaries resulting from the exercise of any rights arising out of defaults on receivables;

(8)           any Lien incurred in the ordinary course of business in connection with workmen’s compensation, unemployment insurance, temporary disability, social security, retiree health or similar laws or regulations or to secure obligations imposed by statute or governmental regulations;

(9)           any Lien in favor of the Partnership or any of its Subsidiaries;

(10)         any Lien in favor of the United States of America or any state thereof, or any department, agency or instrumentality or political subdivision of the United States of America or any state thereof, to secure partial, progress, advance, or other payments pursuant to any contract or statute, or any Debt incurred by the Partnership or any of its Subsidiaries for the purpose of financing all or any part of the purchase price of, or the cost of constructing, developing, repairing or improving, the property or assets subject to such Lien;

(11)         any Lien securing industrial development, pollution control or similar revenue bonds;

(12)         any Lien securing Debt of the Partnership or any of its Subsidiaries, all or a portion of the net proceeds of which are used, substantially concurrent with the funding thereof (and for purposes of determining such “substantial concurrence,” taking into consideration, among other things, required notices to be given to Holders of Outstanding Securities under this Indenture in connection with such refunding, refinancing or repurchase, and the required corresponding durations thereof), to refinance, refund or repurchase all Outstanding Securities under this Indenture, including the amount of all accrued interest thereon and reasonable fees and expenses and premium, if any, incurred by the Partnership or any of its Subsidiaries in connection therewith;

(13)         Liens in favor of any Person to secure obligations under the provisions of any letters of credit, bank guarantees, bonds or surety obligations required or requested by any governmental authority in connection with any contract or statute;

(14)         any Lien upon or deposits of any assets to secure performance of bids, trade contracts or statutory obligations; or

(15)         any Lien to secure performance of Hedging Obligations of the Partnership or any Subsidiary.

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“Person” means any individual, corporation, partnership, joint venture, limited liability company, association, joint-stock company, trust, other entity, unincorporated organization or government, or any agency or political subdivision thereof.

“Place of Payment,” when used with respect to the Securities of any series, means, unless otherwise specifically provided for with respect to such series as contemplated by Section 301, the office or agency of the Partnership in The City of New York and such other place or places where, subject to the provisions of Section 1002, the principal of and any premium and interest on the Securities of that series are payable as contemplated by Section 301.

“Predecessor Security” of any particular Security means every previous Security evidencing all or a portion of the same Debt as that evidenced by such particular Security; and, for the purposes of this definition, any Security authenticated and delivered under Section 306 in exchange for or in lieu of a mutilated, destroyed, lost or stolen Security shall be deemed to evidence the same debt as the mutilated, destroyed, lost or stolen Security.

“Principal Property” means, whether currently owned or leased or subsequently acquired, any pipeline, gathering system, terminal, storage facility, processing plant or other plant or facility located in the United States of America or any territory or political subdivision thereof owned or leased by the Partnership or any of its Subsidiaries and used in transporting, distributing, terminalling, gathering, treating, processing, marketing or storing natural gas, natural gas liquids or other hydrocarbons, except (1) any property or asset consisting of inventories, furniture, office fixtures and equipment (including data processing equipment), vehicles and equipment used on, or useful with, vehicles (but excluding vehicles that generate transportation revenues) and (2) any such pipeline or other plant or facility that, in the good faith opinion of the Board of Directors as evidenced a Board Resolution, is not material in relation to the activities of the Partnership and its Subsidiaries, taken as a whole.

“Principal Subsidiary” means any of the Partnership’s Subsidiaries that owns or leases, directly or indirectly, a Principal Property.

“Redemption Date,” when used with respect to any Security to be redeemed, means the date fixed for such redemption by or pursuant to this Indenture.

“Redemption Price,” when used with respect to any Security to be redeemed, means the price at which it is to be redeemed pursuant to this Indenture.

“Regular Record Date” for the interest payable on any Interest Payment Date on the Securities of any series means the date specified for that purpose as contemplated by Section 301.

“Responsible Officer,” when used with respect to the Trustee, means any officer of the Trustee within the corporate trust department, including any Managing Director, Vice President, assistant secretary, trust officer or assistant trust officer assigned to the Corporate Trust Office, or any other officer of the Trustee customarily performing functions similar to those performed by any of the above designated officers and also means, with respect to a particular corporate trust matter, any other officer of the Trustee to whom such matter is referred because of his

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knowledge of and familiarity with the particular subject, and who shall have direct responsibility for the administration of this Indenture.

“Sale-Leaseback Transaction” means the sale or transfer by the Partnership or any of its Principal Subsidiaries of any Principal Property to a Person (other than the Partnership or a Subsidiary of the Partnership) and the taking back by the Partnership or any Principal Subsidiary of the Partnership, as the case may be, of a lease of such Principal Property.

“Securities” has the meaning stated in the first recital of this Indenture and more particularly means any Securities authenticated and delivered under this Indenture.

“Security Register” and “Security Registrar” have the respective meanings specified in Section 305.

“Special Record Date” for the payment of any Defaulted Interest means a date fixed by the Trustee pursuant to Section 307.

“Stated Maturity,” when used with respect to any Security or any installment of principal thereof or interest thereon, means the date specified in such Security as the fixed date on which the principal of such Security or such installment of principal or interest is due and payable.

“Subsidiary” of any Person means (i) any partnership of which more than 50% of the Capital Interests (considering all partners’ Capital Interests as a single class) is at the time owned or controlled, directly or indirectly, by such Person or one or more of the other Subsidiaries of such Person or combination thereof, or (ii) any corporation, association or other business entity (other than a partnership) of which more than 50% of the total voting power of the Capital Interests entitled (without regard to the occurrence of any contingency) to vote in the election of directors, managers or trustees thereof is at the time owned or controlled, directly or indirectly, by such Person or one or more of the other Subsidiaries of such Person or combination thereof.

“Trust Indenture Act” or “TIA” means the Trust Indenture Act of 1939 as in force at the date as of which this instrument was executed, except as otherwise provided in Section 905; provided, however, that if the Trust Indenture Act of 1939 is amended after such date, “Trust Indenture Act” or “TIA” means, to the extent required by any such amendment, the Trust Indenture Act of 1939 as so amended.

“Trustee” means the Person named as the “Trustee” in the first paragraph of this instrument until a successor Trustee shall have become such pursuant to the applicable provisions of this Indenture, and thereafter “Trustee” shall mean or include each Person who is then a Trustee hereunder, and if at any time there is more than one such Person, “Trustee” as used with respect to the Securities of any series shall mean each Trustee with respect to Securities of that series.

“U.S. Government Obligations” means securities which are (i) direct obligations of the United States for the payment of which its full faith and credit is pledged, or (ii) obligations of a Person controlled or supervised by and acting as an agency or instrumentality of the United States, the payment of which is unconditionally guaranteed as a full faith and credit obligation by the United States, each of which are not callable or redeemable at the option of the issuer thereof.

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“Vice President,” when used with respect to the Partnership, means any vice president of the General Partner, or when used with respect to the Trustee, means any vice president of the Trustee.

SECTION 102.                                                               Incorporation by Reference of Trust Indenture Act.

Whenever this Indenture refers to a provision of the Trust Indenture Act, the provision is incorporated by reference in and made a part of this Indenture.  The following Trust Indenture Act terms used in this Indenture have the following meanings:

“commission” means the Commission.

“indenture securities” means the Securities.

“indenture security holder” means a Holder.

“indenture to be qualified” means this Indenture.

“indenture trustee” or “institutional trustee” means the Trustee.

“obligor” on the indenture securities means the Partnership or any other obligor on the indenture securities.

All terms used in this Indenture that are defined by the Trust Indenture Act, defined by a Trust Indenture Act reference to another statute or defined by a Commission rule under the Trust Indenture Act have the meanings so assigned to them.

SECTION 103.                                                               Compliance Certificates and Opinions.

Upon any application or request by the Partnership to the Trustee to take any action under any provision of this Indenture, the Partnership shall furnish to the Trustee an Officers’ Certificate stating that all conditions precedent, if any, provided for in this Indenture relating to the proposed action have been complied with and an Opinion of Counsel stating that in the opinion of such counsel all such conditions precedent, if any, have been complied with, except that in the case of any such application or request as to which the furnishing of such documents is specifically required by any provision of this Indenture relating to such particular application or request, no additional certificate or opinion need be furnished except as required under Section 314(c) of the Trust Indenture Act.

Every certificate or opinion with respect to compliance with a condition or covenant provided for in this Indenture (except for certificates provided for in Section 1004) shall include:

(1)                                  a statement that each individual signing such certificate or opinion has read such covenant or condition and the definitions herein relating thereto;

(2)                                  a brief statement as to the nature and scope of the examination or investigation upon which the statements or opinions contained in such certificate or opinion are based;

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(3)                                  a statement that, in the opinion of each such individual, he has made such examination or investigation as is necessary to enable him to express an informed opinion as to whether such covenant or condition has been complied with; and

(4)                                  a statement as to whether, in the opinion of each such individual, such condition or covenant has been complied with.

SECTION 104.                                                               Form of Documents Delivered to Trustee.

In any case where several matters are required to be certified by, or covered by an opinion of, any specified Person, it is not necessary that all such matters be certified by, or covered by the opinion of, only one such Person, or that they be so certified or covered by only one document, but one such Person may certify or give an opinion with respect to some matters and one or more other such Persons as to other matters, and any such Person may certify or give an opinion as to such matters in one or several documents.

Any certificate or opinion of an officer of the Partnership or the General Partner may be based, insofar as it relates to legal matters, upon a certificate or opinion of, or representations by, counsel, unless such officer knows, or in the exercise of reasonable care should know, that the certificate or opinion or representations with respect to the matters upon which his certificate or opinion is based are erroneous.  Any such certificate or opinion of counsel may be based, insofar as it relates to factual matters, upon a certificate or opinion of, or representations by, an officer or officers of the Partnership or the General Partner stating that the information with respect to such factual matters is in the possession of the Partnership or the General Partner, unless such counsel knows that the certificate or opinion or representations with respect to such matters are erroneous.

Where any Person is required to make, give or execute two or more applications, requests, consents, certificates, statements, opinions or other instruments under this Indenture, they may, but need not, be consolidated and form one instrument.

SECTION 105.                                                               Acts of Holders; Record Dates.

Any request, demand, authorization, direction, notice, consent, waiver or other action provided or permitted by this Indenture to be given or taken by Holders may be embodied in and evidenced by one or more instruments of substantially similar tenor signed (either physically or by means of a facsimile or an electronic transmission, provided that such electronic transmission is transmitted through the facilities of a Depositary) by such Holders in person or by an agent duly appointed in writing; and, except as herein otherwise expressly provided, such action shall become effective when such instrument or instruments are delivered (either physically or by means of a facsimile or an electronic transmission, provided that such electronic transmission is transmitted through the facilities of a Depositary) to the Trustee and, where it is hereby expressly required, to the Partnership. Such instrument or instruments (and the action embodied therein and evidenced thereby) are herein sometimes referred to as the “Act” of the Holders signing such instrument or instruments.  Proof of execution of any such instrument or of a writing appointing any such agent shall be sufficient for any purpose of this Indenture and (subject to Section 315 of

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the Trust Indenture Act) conclusive in favor of the Trustee and the Partnership, if made in the manner provided in this Section 105.

The fact and date of the execution by any Person of any such instrument or writing may be proved by the affidavit of a witness of such execution or by a certificate of a notary public or other officer authorized by law to take acknowledgments of deeds, certifying that the individual signing such instrument or writing acknowledged to him the execution thereof.  Where such execution is by a signer acting in a capacity other than his individual capacity, such certificate or affidavit shall also constitute sufficient proof of his authority.  The fact and date of the execution of any such instrument or writing, or the authority of the Person executing the same, may also be proved in any other manner which the Trustee deems sufficient.

The ownership, principal amount and serial numbers of Securities held by any Person, and the date of commencement of such Person’s holding the same, shall be proved by the Security Register.

Any request, demand, authorization, direction, notice, consent, waiver or other action of the Holder of any Security shall bind every future Holder of the same Security and the Holder of every Security issued upon the registration of transfer thereof or in exchange therefor or in lieu thereof in respect of anything done, omitted or suffered to be done by the Trustee or the Partnership in reliance thereon, regardless of whether notation of such action is made upon such Security.

Without limiting the foregoing, a Holder entitled hereunder to give or take any action hereunder with regard to any particular Security may do so with regard to all or any part of the principal amount of such Security or by one or more duly appointed agents each of which may do so pursuant to such appointment with regard to all or any different part of such principal amount.

The Partnership may set any day as the record date for the purpose of determining the Holders of Outstanding Securities of any series entitled to give or take any request, demand, authorization, direction, notice, consent, waiver or other action provided or permitted by this Indenture to be given or taken by Holders of Securities of such series, but the Partnership shall have no obligation to do so.  With regard to any record date set pursuant to this paragraph, the Holders of Outstanding Securities of the relevant series on such record date (or their duly appointed agents), and only such Persons, shall be entitled to give or take the relevant action, regardless of whether such Holders remain Holders after such record date.

SECTION 106.                                                               Notices, Etc. to Trustee and Partnership.

Any request, demand, authorization, direction, notice, consent, waiver or Act of Holders or other document provided or permitted by this Indenture to be made upon, given or furnished to, or filed with,

(1)                                  the Trustee by any Holder or by the Partnership shall be sufficient for every purpose hereunder if made, given, furnished or filed in writing and faxed or mailed, first class postage prepaid, to or with the Trustee at its Corporate Trust Office, and, with respect to deliveries permitted to be made by electronic means to the Trustee pursuant to

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Section 704 of the Indenture, at arlene.thelwell@bnymellon.com or such other email address as the Trustee shall specify from time to time; or

(2)                                  the Partnership by the Trustee or by any Holder shall be sufficient for every purpose hereunder (unless otherwise herein expressly provided), as well as for service of process on the Partnership, if in writing and mailed, first-class postage prepaid, to the Partnership addressed to it at the address of its principal office specified in the first paragraph of this instrument or to Fax No. (403) 920-2467 to the attention of the Corporate Secretary, or at any other address previously furnished in writing to the Trustee by the Partnership.

SECTION 107.                                                               Notice to Holders; Waiver.

Where this Indenture provides for notice to Holders of any event, such notice shall be sufficiently given (unless otherwise herein expressly provided) if in writing and mailed, first-class postage prepaid (if international mail, by air mail), to each Holder affected by such event, at his address as it appears in the Security Register, not later than the latest date (if any), and not earlier than the earliest date (if any), prescribed for the giving of such notice.  In any case where notice to Holders is given by mail, neither the failure to mail such notice, nor any defect in any notice so mailed, to any particular Holder shall affect the sufficiency of such notice with respect to other Holders.  Any notice mailed to a Holder in the manner herein prescribed shall be conclusively deemed to have been received by such Holder, whether or not such Holder actually receives such notice.

Where this Indenture provides for notice in any manner, such notice may be waived in writing by the Person entitled to receive such notice, either before or after the event, and such waiver shall be the equivalent of such notice.  Waivers of notice by Holders shall be filed with the Trustee, but such filing shall not be a condition precedent to the validity of any action taken in reliance upon such waiver.

In case by reason of the suspension of regular mail service or by reason of any other cause it shall be impracticable to give such notice by mail, then such notification as shall be made with the approval of the Trustee shall constitute a sufficient notification for every purpose hereunder.

SECTION 108.                                                               Conflict with Trust Indenture Act.

If any provision hereof limits, qualifies or conflicts with a provision of the Trust Indenture Act that is required under such Act to be a part of and govern this Indenture, the latter provision shall control.  If any provision of this Indenture modifies or excludes any provision of the Trust Indenture Act that may be so modified or excluded, the latter provision shall be deemed to apply to this Indenture as so modified or excluded, as the case may be.

SECTION 109.                                                               Effect of Headings and Table of Contents.

The Article and Section headings herein and the Table of Contents are for convenience only and shall not affect the construction hereof.

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SECTION 110.                                                               Successors and Assigns.

All covenants and agreements in this Indenture by the Partnership shall bind its successors and assigns, whether so expressed or not.

SECTION 111.                                                               Separability Clause.

In case any provision in this Indenture or in the Securities shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions shall not in any way be affected or impaired thereby.

SECTION 112.                                                               Benefits of Indenture.

Nothing in this Indenture or in the Securities, express or implied, shall give to any Person, other than the parties hereto and their successors hereunder and the Holders, any benefit or any legal or equitable right, remedy or claim under this Indenture.

SECTION 113.                                                               Governing Law.

This Indenture and the Securities shall be governed by and construed in accordance with the laws of the State of New York, without regard to conflict of law principles thereof that would require the application of the laws of another jurisdiction.

SECTION 114.                                                               Legal Holidays.

In any case where any Interest Payment Date, Redemption Date or Stated Maturity of any Security shall not be a Business Day at any Place of Payment, then (notwithstanding any other provision of this Indenture or of the Securities (other than a provision of the Securities of any series that specifically states that such provision shall apply in lieu of this Section 114)) payment of interest or principal (and any premium) need not be made at such Place of Payment on such date, but may be made on the next succeeding Business Day at such Place of Payment with the same force and effect as if made on the Interest Payment Date or Redemption Date, or at the Stated Maturity, provided that no additional interest shall accrue for the period from and after such Interest Payment Date, Redemption Date or Stated Maturity, as the case may be, to the next Business Day with respect to that payment on account of such delay.

SECTION 115.                                                               Securities in a Composite Currency, Currency Unit or Foreign Currency.

Unless otherwise specified in an Officers’ Certificate delivered pursuant to Section 301 of this Indenture with respect to a particular series of Securities, whenever for purposes of this Indenture any action may be taken by the Holders of a specified percentage in aggregate principal amount of Securities of all series or all series affected by a particular action at the time Outstanding and, at such time, there are Outstanding Securities of any series which are denominated in a coin, currency or currencies other than Dollars (including, but not limited to, any composite currency, currency units or Foreign Currency), then the principal amount of Securities of such series which shall be deemed to be Outstanding for the purpose of taking such action shall be that amount of Dollars that could be obtained for such amount at the Market

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Exchange Rate. For purposes of this Section 115, the term “Market Exchange Rate” shall mean the noon Dollar buying rate in The City of New York for cable transfers of such currency or currencies as published by the Federal Reserve Bank of New York, as of the most recent available date.  If such Market Exchange Rate is not so available for any reason with respect to such currency, the Partnership shall use, in its sole discretion and without liability on its part, such quotation of the Federal Reserve Bank of New York as of the most recent available date, or quotations or rates of exchange from one or more major banks in The City of New York or in the country of issue of the currency in question, which for purposes of euros shall be Brussels, Belgium, or such other quotations or rates of exchange as the Partnership shall deem appropriate.  The provisions of this paragraph shall apply in determining the equivalent principal amount in respect of Securities of a series denominated in a currency other than Dollars in connection with any action taken by Holders of Securities pursuant to the terms of this Indenture.

All decisions and determinations of the Partnership regarding the Market Exchange Rate or any alternative determination provided for in the preceding paragraph shall be in its sole discretion and shall, in the absence of manifest error, be conclusive to the extent permitted by law for all purposes and irrevocably binding upon the Trustee and all Holders.

SECTION 116.                                                               Judgment Currency.

The Partnership agrees, to the fullest extent that it may effectively do so under applicable law, that (a) if for the purpose of obtaining judgment in any court it is necessary to convert the sum due in respect of the principal of or interest on the Securities of any series (the “Required Currency”) into a currency in which a judgment will be rendered (the “Judgment Currency”), the rate of exchange used shall be the rate at which, in accordance with normal banking procedures, a financial institution appointed by the Partnership for such purposes could purchase in The City of New York the Required Currency with the Judgment Currency on the day on which final unappealable judgment is entered, unless such day is not a Banking Day, then, to the extent permitted by applicable law, the rate of exchange used shall be the rate at which, in accordance with normal banking procedures, such financial institution appointed by the Partnership for such purposes could purchase in The City of New York the Required Currency with the Judgment Currency on the Banking Day next preceding the day on which final unappealable judgment is entered and (b) its obligations under this Indenture to make payments in the Required Currency (i) shall not be discharged or satisfied by any tender, or any recovery pursuant to any judgment (whether or not entered in accordance with subsection (a)), in any currency other than the Required Currency, except to the extent that such tender or recovery shall result in the actual receipt, by the payee, of the full amount of the Required Currency expressed to be payable in respect of such payments, (ii) shall be enforceable as an alternative or additional cause of action for the purpose of recovering in the Required Currency the amount, if any, by which such actual receipt shall fall short of the full amount of the Required Currency so expressed to be payable and (iii) shall not be affected by judgment being obtained for any other sum due under this Indenture.

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SECTION 117.                                                               Language of Notices, Etc.

Any request, demand, authorization, direction, notice, consent, waiver or Act required or permitted under this Indenture shall be in the English language, except that any published notice may be in an official language of the country of publication.

SECTION 118.                                                               Non-Recourse to the General Partner; No Personal Liability of Officers, Directors, Employees or Partners.

Obligations of the Partnership under this Indenture and the Securities hereunder are non-recourse to the General Partner, and its Affiliates (other than the Partnership), and payable only out of cash flow and assets of the Partnership.  The Trustee, and each Holder of a Security by its acceptance thereof, will be deemed to have agreed in this Indenture that (1) neither the General Partner nor its assets (nor any of its Affiliates other than the Partnership, nor their respective assets) shall be liable for any of the obligations of the Partnership under this Indenture or such Securities, and (2) no director, officer, employee, stockholder or unitholder, as such, of the Partnership, the Trustee, the General Partner or any Affiliate of any of the foregoing entities shall have any personal liability in respect of the obligations of the Partnership under this Indenture or such Securities by reason of his, her or its status.

SECTION 119.                                                               Waiver of Jury Trial.

THE PARTIES HERETO HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVE, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL ACTION OR PROCEEDING RELATING TO THIS INDENTURE AND FOR ANY COUNTERCLAIM RELATING THERETO. EACH PARTY ACKNOWLEDGES THAT THE OTHER PARTY HERETO IS ENTERING INTO THIS INDENTURE IN RELIANCE UPON SUCH WAIVER.

SECTION 120.                                                               Submission to Jurisdiction.

Each of the parties hereto hereby irrevocably and unconditionally submits to the non-exclusive jurisdiction of the United States District Court for the Southern District of New York or of any New York State court (in either case sitting in Manhattan, New York City), in each case with all applicable courts of appeal therefrom, for purposes of all legal proceedings arising out of or relating to this Indenture (including any indenture supplemental hereto) or the transactions contemplated hereby; provided that nothing herein shall be deemed to limit the ability of any party to this Indenture to bring suit against any other party to this Indenture in any other permissible jurisdiction.  Each of the parties hereto hereby irrevocably waives, to the fullest extent permitted by applicable law, any objection that it may now or hereafter have to the laying of the venue of any such proceeding brought in such state or federal court in New York City of any claim that any such proceeding brought in such a court has been brought in an inconvenient forum and any objection based on place of residence or domicile.  Nothing herein shall be deemed to require the Trustee to submit to the jurisdiction of a non-U.S. court.

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ARTICLE II
SECURITY FORMS

SECTION 201.                                                               Forms Generally.

The Securities of each series shall be in substantially the form set forth in this Article II, or in such other form or forms as shall be established by or pursuant to a Board Resolution or in one or more indentures supplemental hereto, in each case with such appropriate insertions, omissions, substitutions and other variations as are required or permitted by this Indenture, and may have such letters, numbers or other marks of identification and such legends or endorsements placed thereon as may be required to comply with the rules of any securities exchange or automated quotation system on which the Securities of such series may be listed or traded or Depositary therefor or as may, consistently herewith, be determined by the officers executing such Securities, as evidenced by their execution of the Securities.  If the form of Securities of any series is established by action taken pursuant to a Board Resolution, a copy of an appropriate record of such action shall be certified by an authorized officer or other authorized Person on behalf of the Partnership and delivered to the Trustee at or prior to the delivery of the Partnership Order contemplated by Section 303 for the authentication and delivery of such Securities.

The definitive Securities shall be printed, lithographed or engraved on steel engraved borders or may be produced in any other manner, all as determined by the officers executing such Securities, as evidenced by their execution of such Securities.

The forms of Global Securities of any series shall have such provisions and legends as are customary for Securities of such series in global form, including without limitation any legend required by the Depositary for the Securities of such series.

SECTION 202.                                                               Form of Face of Security.

[If the Security is an Original Issue Discount Security, insert — FOR PURPOSES OF SECTION 1275 OF THE UNITED STATES INTERNAL REVENUE CODE OF 1986, AS AMENDED, THE AMOUNT OF THE ORIGINAL ISSUE DISCOUNT IS               , THE ISSUE DATE IS               , 20    [AND][,] THE YIELD TO MATURITY IS               [,] [AND THE ORIGINAL ISSUE DISCOUNT FOR THE SHORT ACCRUAL PERIOD IS               AND THE METHOD USED TO DETERMINE THE YIELD THEREFOR IS      ]]

[Insert any other legend required by the United States Internal Revenue Code and the regulations thereunder.]

[If a Global Security, insert legend required by Section 204 of the Indenture.]

[If applicable, insert — UNLESS THIS SECURITY IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION, TO THE PARTNERSHIP OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY SECURITY ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST

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COMPANY (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.]

TC PipeLines, LP
[TITLE OF SECURITY]

TC PIPELINES, LP, a Delaware limited partnership (herein called the “Partnership,” which term includes any successor Person under the Indenture hereinafter referred to), for value received, hereby promises to pay to [             ], or registered assigns, the principal sum of        United States Dollars on            [if the Security is to bear interest prior to Maturity, insert — , and to pay interest thereon from                , or from the most recent Interest Payment Date to which interest has been paid or duly provided for, semi-annually on       and         in each year, commencing ,           , at the rate of       % per annum, until the principal hereof is paid or made available for payment [if applicable, insert — , and at the rate of      % per annum on any overdue principal and premium and on any overdue installment of interest]. [If applicable, insert — The amount of interest payable for any period shall be computed on the basis of twelve 30-day months and a 360-day year.  The amount of interest payable for any partial period shall be computed on the basis of a 360-day year of twelve 30-day months and the days elapsed in any partial month.  In the event that any date on which interest is payable on this Security is not a Business Day, then a payment of the interest payable on such date will be made on the next succeeding day which is a Business Day (and without any interest or other payment in respect of any such delay) with the same force and effect as if made on the date the payment was originally payable.  A “Business Day” shall mean, when used with respect to any Place of Payment, each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking institutions in that Place of Payment are authorized or obligated by law, executive order or regulation to close.]  The interest so payable, and punctually paid or duly provided for, on any Interest Payment Date will, as provided in such Indenture, be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date for such interest, which shall be the              or            (whether or not a Business Day), as the case may be, next preceding such Interest Payment Date.  Any such interest not so punctually paid or duly provided for shall forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to Holders of Securities of this series not less than 10 days prior to such

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Special Record Date, or be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange or automated quotation system on which the Securities of this series may be listed or traded, and upon such notice as may be required by such exchange or automated quotation system, all as more fully provided in such Indenture].

[If the Security is not to bear interest prior to Maturity, insert — The principal of this Security shall not bear interest except in the case of a default in payment of principal upon acceleration, upon redemption or at Stated Maturity and in such case the overdue principal of this Security shall bear interest at the rate of    % per annum (to the extent that the payment of such interest shall be legally enforceable), which shall accrue from the date of such default in payment to the date payment of such principal has been made or duly provided for. Interest on any overdue principal shall be payable on demand.  Any such interest on any overdue principal that is not so paid on demand shall bear interest at the rate of    % per annum (to the extent that the payment of such interest shall be legally enforceable), which shall accrue from the date of such demand for payment to the date payment of such interest has been made or duly provided for, and such interest shall also be payable on demand.]

[If a Global Security, insert — Payment of the principal of [(and premium, if any)] and [if applicable, insert — any such] interest on this Security will be made by transfer of immediately available funds to a bank account in           designated by the Holder in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts [state other currency].]

[If a Definitive Security, insert — Payment of the principal of [(and premium, if any)] and [if applicable, insert — any such] interest on this Security will be made at the office or agency of the Partnership maintained for that purpose in           , [in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts] [state other currency] [or subject to any laws or regulations applicable thereto and to the right of the Partnership (as provided in the Indenture) to rescind the designation of any such Paying Agent, at the [main] offices of          in          and           in            , or at such other offices or agencies as the Partnership may designate, by [United States Dollar] [state other currency] check drawn on, or transfer to a [United States Dollar] account maintained by the payee with, a bank in The City of New York (so long as the applicable Paying Agent has received proper transfer instructions in writing at least [    ] days prior to the payment date)] [if applicable, insert —; provided, however, that payment of interest may be made at the option of the Partnership by [United States Dollar] [state other currency] check mailed to the addresses of the Persons entitled thereto as such addresses shall appear in the Security Register] [or by transfer to a [United States Dollar] [state other currency] account maintained by the payee with a bank in The City of New York [state other Place of Payment] (so long as the applicable Paying Agent has received proper transfer instructions in writing by the Record Date prior to the applicable Interest Payment Date)].]

Reference is hereby made to the further provisions of this Security set forth on the reverse hereof, which further provisions shall for all purposes have the same effect as if set forth at this place.

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Unless the certificate of authentication hereon has been executed by the Trustee referred to on the reverse hereof by manual signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose.

IN WITNESS WHEREOF, the Partnership has caused this instrument to be duly executed.

Dated:

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SECTION 203.                     Form of Reverse of Security.

This Security is one of a duly authorized issue of senior securities of the Partnership (herein called the “Securities”), issued and to be issued in one or more series under an Indenture dated as of June 17, 2011 (the “Indenture”), between the Partnership and The Bank of New York Mellon, as Trustee (the “Trustee,” which term includes any successor trustee under the Indenture), to which Indenture and all indentures supplemental thereto reference is hereby made for a statement of the respective rights, limitations of rights, obligations, duties and immunities thereunder of the Partnership, the Trustee and the Holders of the Securities and of the terms upon which the Securities are, and are to be, authenticated and delivered.  As provided in the Indenture, the Securities may be issued in one or more series, which different series may be issued in various aggregate principal amounts, may mature at different times, may bear interest, if any, at different rates, may be subject to different redemption provisions, if any, may be subject to different sinking, purchase or analogous funds, if any, may be subject to different covenants and Events of Default and may otherwise vary as in the Indenture provided or permitted.  This Security is one of the series designated on the face hereof [if applicable, insert — , limited in aggregate principal amount to U.S.$     ].

[If applicable, insert — The Securities of this series are subject to redemption upon not less than 30 nor more than 60 days’ notice by mail, [if applicable, insert — (1) on          in any year commencing with the year     and ending with the year      through operation of the sinking fund for this series at a Redemption Price equal to 100% of the principal amount, and (2)] at any time [if applicable, insert — on or after       ,       ], as a whole or in part, at the election of the Partnership, at the following Redemption Prices (expressed as percentages of the principal amount):  If redeemed [if applicable, insert — on or before           , %, and if redeemed] during the 12-month period beginning of the years indicated,

and thereafter at a Redemption Price equal to    % of the principal amount, together in the case of any such redemption [if applicable, insert — (whether through operation of the sinking fund or otherwise)] with accrued interest to the Redemption Date, but interest installments whose Stated Maturity is on or prior to such Redemption Date will be payable to the Holders of such Securities, or one or more Predecessor Securities, of record at the close of business on the relevant Record Dates referred to on the face hereof, all as provided in the Indenture.]

[If applicable, insert — The Securities of this series are subject to redemption upon not less than 30 nor more than 60 days’ notice by mail, (1) on            in any year commencing with the year      and ending with the year       through operation of the sinking fund for this series at the Redemption Prices for redemption through operation of the sinking fund (expressed as percentages of the principal amount) set forth in the table below, and (2) at any time [if applicable, insert — on or after           ], as a whole or in part, at the election of the Partnership, at the Redemption Prices for redemption otherwise than through operation of the sinking fund

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(expressed as percentages of the principal amount) set forth in the table below: If redeemed during the 12-month period beginning           of the years indicated,

and thereafter at a Redemption Price equal to % of the principal amount, together in the case of any such redemption (whether through operation of the sinking fund or otherwise) with accrued interest to the Redemption Date, but interest installments whose Stated Maturity is on or prior to such Redemption Date will be payable to the Holders of such Securities, or one or more Predecessor Securities, of record at the close of business on the relevant Record Dates referred to on the face hereof, all as provided in the Indenture.]

[If applicable, insert — The sinking fund for this series provides for the redemption in each year beginning with the year      and ending with the year      of [if applicable, — not less than $        (“mandatory sinking fund”) and not more than] $          aggregate principal amount of Securities of this series.  Securities of this series acquired or redeemed by the Partnership otherwise than through [if applicable, — mandatory] sinking fund payments may be credited against subsequent [if applicable, — mandatory] sinking fund payments otherwise required to be made [if applicable, — in the inverse order in which they become due].]

[If the Security is subject to redemption in part of any kind, insert — In the event of redemption of this Security in part only, a new Security or Securities of this series and of like tenor for the unredeemed portion hereof will be issued in the name of the Holder hereof upon the cancellation hereof.]

[If applicable, insert — The Securities of this series are not redeemable prior to Stated Maturity.]

[If the Security is not an Original Issue Discount Security, insert — If an Event of Default with respect to Securities of this series shall occur and be continuing, the principal of the Securities of this series may be declared due and payable in the manner and with the effect provided in the Indenture.]

[If the Security is an Original Issue Discount Security, insert — If an Event of Default with respect to Securities of this series shall occur and be continuing, an amount of principal of the Securities of this series may be declared due and payable in the manner and with the effect provided in the Indenture.  Such amount shall be equal to [insert — formula for determining the amount].  Upon payment (1) of the amount of principal so declared due and payable, and (2) of interest on any overdue principal and overdue interest (in each case to the extent that the payment of such interest shall be legally enforceable), all of the Partnership’s obligations in respect of the payment of the principal of and interest, if any, on the Securities of this series shall

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terminate other than those obligations which expressly survive by their terms under the Indenture, including indemnification of the Trustee.]

The Indenture permits, with certain exceptions as therein provided, the amendment thereof and the modification of the rights and obligations of the Partnership and the rights of the Holders of the Securities of each series to be affected under the Indenture at any time by the Partnership and the Trustee with the consent of the Holders of a majority in principal amount of the Securities at the time Outstanding of all series to be affected (voting as one class).  The Indenture also contains provisions permitting the Holders of specified percentages in principal amount of the Securities of each series at the time Outstanding, on behalf of the Holders of all Securities of such series, to waive compliance by the Partnership with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences.  Any such consent or waiver by the Holder of this Security shall be conclusive and binding upon such Holder and upon all future Holders of this Security and of any Security issued upon the registration of transfer hereof or in exchange herefor or in lieu hereof, regardless of whether notation of such consent or waiver is made upon this Security.

As provided in and subject to the provisions of the Indenture, the Holder of this Security shall not have the right to institute any proceeding with respect to the Indenture or for the appointment of a receiver or trustee or for any other remedy thereunder, unless such Holder shall have previously given the Trustee written notice of a continuing Event of Default with respect to the Securities of this series, the Holders of not less than 25% in principal amount of the Securities of this series at the time Outstanding shall have made written request to the Trustee to institute proceedings in respect of such Event of Default as Trustee and offered the Trustee reasonable indemnity and the Trustee shall not have received from the Holders of a majority in principal amount of Securities of this series at the time Outstanding a direction inconsistent with such request, and shall have failed to institute any such proceeding, for 60 days after receipt of such notice, request and offer of indemnity. The foregoing shall not apply to any suit instituted by the Holder of this Security for the enforcement of any payment of principal hereof or [any premium or] interest hereon on or after the respective due dates expressed herein.

No reference herein to the Indenture and no provision of this Security or of the Indenture shall alter or impair the obligation of the Partnership, which is absolute and unconditional, to pay the principal of and [any premium and] interest on this Security at the times, place(s) and rate, and in the coin or currency, herein prescribed.

[If a Global Security, insert — This Global Security or portion hereof may not be exchanged for Definitive Securities of this series except in the limited circumstances provided in the Indenture.

The holders of beneficial interests in this Global Security will not be entitled to receive physical delivery of Definitive Securities except as described in the Indenture and will not be considered the Holders hereof for any purpose under the Indenture.]

[If a Definitive Security, insert — As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Security is registerable in the Security Register, upon surrender of this Security for registration of transfer at the office or agency of the

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Partnership in [if applicable, insert — any place where the principal of and any premium and interest on this Security are payable] [if applicable, insert — The City of New York [, or, subject to any laws or regulations applicable thereto and to the right of the Partnership (limited as provided in the Indenture) to rescind the designation of any such transfer agent, at the [main] offices of                                in                                 and                                    in                             or at such other offices or agencies as the Partnership may designate]], duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Partnership and the Security Registrar duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Securities of this series and of like tenor, of authorized denominations and for the same aggregate principal amount, will be issued to the designated transferee or transferees.]

The Securities of this series are issuable only in registered form without coupons in denominations of U.S.$                    [state other currency] and any integral multiple thereof.  As provided in the Indenture and subject to certain limitations therein set forth, Securities of this series are exchangeable for a like aggregate principal amount of Securities of this series and of like tenor of a different authorized denomination, as requested by the Holder surrendering the same.

No service charge shall be made for any such registration of transfer or exchange, but the Partnership may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith.

Prior to due presentment of this Security for registration of transfer, the Partnership, the Trustee and any agent of the Partnership or the Trustee may treat the Person in whose name this Security is registered as the owner hereof for all purposes, regardless of whether this Security is overdue, and neither the Partnership, the Trustee nor any such agent shall be affected by notice to the contrary.

Obligations of the Partnership under the Indenture and the Securities thereunder, including this Security, are non-recourse to TC PipeLines GP, Inc. (the “General Partner”) and its Affiliates (other than the Partnership), and payable only out of cash flow and assets of the Partnership.  The Trustee, and each Holder of a Security by its acceptance hereof, will be deemed to have agreed in the Indenture that (1) neither the General Partner nor its assets (nor any of its Affiliates other than the Partnership, nor their respective assets) shall be liable for any of the obligations of the Partnership under the Indenture or such Securities, including this Security, and (2) no director, officer, employee, stockholder or unitholder, as such, of the Partnership, the Trustee, the General Partner or any Affiliate of any of the foregoing entities shall have any personal liability in respect of the obligations of the Partnership under the Indenture or such Securities by reason of his, her or its status.

The Indenture provides that the Partnership (a) will be discharged from any and all obligations in respect of the Securities (except for certain obligations described in the Indenture), or (b) need not comply with certain restrictive covenants of the Indenture, in each case if the Partnership deposits, in trust, with the Trustee money or U.S. Government Obligations (or a combination thereof) which through the payment of interest thereon and principal thereof in accordance with their terms will provide money, in an amount sufficient to pay all the principal

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of and interest on the Securities, but such money need not be segregated from other funds except to the extent required by law.

This Security shall be governed by and construed in accordance with the laws of the State of New York without regard to conflict of law principles thereof that would require the application of the laws of another jurisdiction.

All terms used in this Security which are defined in the Indenture shall have the meanings assigned to them in the Indenture.

[If a Definitive Security, insert as a separate page —

FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s) and transfer(s) unto                                     (Please Print or Typewrite Name and Address of Assignee) the within instrument of TC PIPELINES, LP and does hereby irrevocably constitute and appoint                          Attorney to transfer said instrument on the books of the within-named Partnership, with full power of substitution in the premises.

Please Insert Social Security or Other Identifying Number of Assignee:

(Participant in a Recognized Signature Guaranty Medallion Program)

NOTICE:  The signature to this assignment must correspond with the name as written upon the face of the within instrument in every particular, without alteration or enlargement or any change whatever.]

SECTION 204.                     Global Securities.

Every Global Security authenticated and delivered hereunder shall bear a legend in substantially the following form:

THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A NOMINEE THEREOF.  THIS SECURITY MAY NOT BE TRANSFERRED TO, OR REGISTERED OR EXCHANGED FOR SECURITIES REGISTERED IN THE NAME OF, ANY PERSON OTHER THAN THE DEPOSITARY OR A NOMINEE THEREOF AND NO SUCH TRANSFER MAY BE REGISTERED, EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE.  EVERY SECURITY AUTHENTICATED AND DELIVERED UPON REGISTRATION OF TRANSFER OF, OR IN EXCHANGE FOR OR IN LIEU OF, THIS

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SECURITY SHALL BE A GLOBAL SECURITY SUBJECT TO THE FOREGOING, EXCEPT IN SUCH LIMITED CIRCUMSTANCES.

If Securities of a series are issuable in whole or in part in the form of one or more Global Securities, as specified as contemplated by Section 301, then, notwithstanding clause (9) of Section 301 and the provisions of Section 302, any Global Security shall represent such of the Outstanding Securities of such series as shall be specified therein and may provide that it shall represent the aggregate amount of Outstanding Securities from time to time endorsed thereon and that the aggregate amount of Outstanding Securities represented thereby may from time to time be reduced or increased, as the case may be, to reflect exchanges, transfers or redemptions. Any endorsement of a Global Security to reflect the amount, or any reduction or increase in the amount, of Outstanding Securities represented thereby shall be made in such manner and upon instructions given by such Person or Persons as shall be specified therein or in a Partnership Order.  Subject to the provisions of Sections 303, 304 and 305, the Trustee shall deliver and redeliver any Global Security in the manner and upon instructions given by the Person or Persons specified therein or in the applicable Partnership Order.  Any instructions by the Partnership with respect to endorsement or delivery or redelivery of a Global Security shall be in a Partnership Order (which need not comply with Section 102 and need not be accompanied by an Opinion of Counsel).

The provisions of the last sentence of Section 303 shall apply to any Security represented by a Global Security if such Security was never issued and sold by the Partnership and the Partnership delivers to the Trustee the Global Security together with a Partnership Order (which need not comply with Section 102 and need not be accompanied by an Opinion of Counsel) with regard to the reduction or increase, as the case may be, in the principal amount of Securities represented thereby, together with the written statement contemplated by the last sentence of Section 303.

SECTION 205.                     Form of Trustee’s Certificate of Authentication.

The Trustee’s certificate of authentication shall be in substantially the following form:

This is one of the Securities of the series designated therein referred to in the within-mentioned Indenture.

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ARTICLE III
THE SECURITIES

SECTION 301.                                                                 Amount Unlimited; Issuable in Series.

The aggregate principal amount of Securities which may be authenticated and delivered under this Indenture is unlimited.

The Securities may be issued in one or more series.  There shall be established in or pursuant to a Board Resolution and set forth, or determined in the manner provided, in an Officers’ Certificate, or established in one or more indentures supplemental hereto, prior to the issuance of Securities of any series,

(1)           the title of the Securities of the series (which shall distinguish the Securities of the series from all other Securities and which may be a part of a series of Securities previously issued);

(2)           any limit upon the aggregate principal amount of the Securities of the series which may be authenticated and delivered under this Indenture (except for Securities authenticated and delivered upon registration of transfer of, or in exchange for, or in lieu of, other Securities of the series pursuant to Sections 304, 305, 306, 906 or 1107 and except for any Securities which, pursuant to Section 303, are deemed never to have been authenticated and delivered hereunder);

(3)           the Person to whom any interest on a Security of the series shall be payable, if other than the Person in whose name that Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date for such interest;

(4)           the date or dates on which the principal of the Securities of the series is payable or the method of determination thereof;

(5)           the rate or rates at which the Securities of the series shall bear interest, if any, or the formula, method or provision pursuant to which such rate or rates are determined, the date or dates from which such interest shall accrue, or the method of determination thereof, the Interest Payment Dates on which any such interest shall be payable and the Regular Record Date for any interest payable on any Interest Payment Date;

(6)           the place or places where, subject to the provisions of Section 1002, the principal of and any premium and interest on Securities of the series shall be payable, Securities of the series may be surrendered for registration of transfer, Securities of the series may be surrendered for exchange and notices, and demands to or upon the Partnership in respect of the Securities of the series and this Indenture may be served;

(7)           the period or periods within which, the price or prices at which and the terms and conditions upon which Securities of the series may be redeemed, in whole or in part, at the option of the Partnership;

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(8)           the obligation, if any, of the Partnership to redeem or purchase Securities of the series pursuant to any sinking fund or analogous provisions or at the option of a Holder thereof and the period or periods within which, the price or prices at which and the terms and conditions upon which Securities of the series shall be redeemed or purchased, in whole or in part, pursuant to such obligation;

(9)           if other than denominations of $1,000 and any integral multiple thereof, the denominations in which Securities of the series shall be issuable;

(10)         whether payment of principal of and premium, if any, and interest, if any, on the Securities of the series shall be without deduction for taxes, assessments or governmental charges paid by Holders of the series;

(11)         if other than the principal amount thereof, the portion of the principal amount which shall be payable upon declaration of acceleration of the Maturity thereof pursuant to Section 502;

(12)         if other than Dollars, the currency or currencies, including composite currencies, currency units or Foreign Currency, in which payment of the principal of and any premium and interest on the Securities of the series shall be payable, and, if other than as specified in Section 115, the manner of determining the equivalent thereof in Dollars for purposes of the determination of “Outstanding” in Section 101;

(13)         if the amount of payments of principal of and any premium or interest on any Securities of the series may be determined with reference to an index, the manner in which such amounts shall be determined;

(14)         if the principal of or any premium or interest on any Securities of the series is to be payable, at the election of the Partnership or a Holder thereof, in one or more currencies or currency units other than that or those in which the Securities are stated to be payable, the currency, currencies or currency units in which payment of the principal of and any premium and interest on Securities of such series as to which such election is made shall be payable, and the periods within which and the terms and conditions upon which such election is to be made;

(15)         the right, if any, of the Partnership to defer payments of interest by extending the interest payment periods and specify the duration of such extension, the Interest Payment Dates on which such interest shall be payable and whether and under what circumstances additional interest on amounts deferred shall be payable;

(16)         if and as applicable, that the Securities of the series shall be issuable in whole or in part in the form of one or more Global Securities and, in such case, the Depositary or Depositaries for such Global Security or Global Securities and any circumstances other than those set forth in Section 305 in which any such Global Security may be transferred to, and registered and exchanged for Securities registered in the name of, a Person other than the Depositary for such Global Security or a nominee thereof and in which any such transfer may be registered;

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(17)         any deletions from, modifications of or additions to the Events of Default set forth in Section 501 or the covenants of the Partnership set forth in Article X with respect to the Securities of such series;

(18)         whether and under which circumstances the Partnership will pay additional amounts on the Securities of the series held by a Person who is not a U.S. person in respect of any tax, assessment or governmental charge withheld or deducted, and, if so, whether the Partnership will have the option to redeem the Securities of the series rather than pay such additional amounts;

(19)         if the Securities of the series are to be issuable in definitive form (whether upon original issue or upon exchange of a temporary Security of such series) only upon receipt of certain certificates or other documents or satisfaction of other conditions, the form and terms of such certificates, documents or conditions;

(20)         if the Securities of the series are convertible into or exchangeable for any other security or property of the Partnership, including, without limitation, securities of another Person held by the Partnership or its Affiliates and, if so, the terms thereof;

(21)         if other than as provided in Sections 1302 and 1303, the means of defeasance or covenant defeasance as may be specified for the Securities of the series;

(22)         if other than the Trustee, the identity of the Security Registrar and any Paying Agent; and

(23)         any other terms of the Securities of the series (which terms shall not be prohibited by the provisions of this Indenture).

All Securities of any one series shall be substantially identical except as to denomination and except as may otherwise be provided in or pursuant to the Board Resolution referred to above and (subject to Section 303) set forth, or determined in the manner provided, in the Officers’ Certificate referred to above or in any such indenture supplemental hereto.

All Securities of any one series need not be issued at the same time and, unless otherwise provided, a series may be reopened, without the consent of the Holders, for increases in the aggregate principal amount of such series of Securities and issuances of additional Securities of such series or for the establishment of additional terms with respect to the Securities of such series.

If any of the terms of the series are established by action taken by or pursuant to a Board Resolution, a copy of an appropriate record of such action shall be certified by an authorized officer or other authorized person of the General Partner on behalf of the Partnership and delivered to the Trustee at or prior to the delivery of the Officers’ Certificate setting forth, or providing the manner for determining, the terms of the series.

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With respect to Securities of a series subject to a Periodic Offering, such Board Resolution or Officers’ Certificate may provide general terms for Securities of such series and provide either that the specific terms of particular Securities of such series shall be specified in a Partnership Order, or that such terms shall be determined by the Partnership, or one or more of the Partnership’s agents designated in an Officers’ Certificate, in accordance with a Partnership Order.  Unless otherwise specifically provided with respect to a particular series of Securities, at any time the Partnership may purchase Securities in the open market, by tender or by contract.