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                                                                   EXHIBIT 10.1


                               FIRST AMENDMENT TO
                           REVOLVING CREDIT AGREEMENT


                  THIS FIRST AMENDMENT TO REVOLVING CREDIT AGREEMENT (this
"Amendment") dated effective March 29, 2006, is entered into by and among
NORTHERN BORDER PIPELINE COMPANY, a Texas general partnership (the "Borrower"),
the several banks and other financial institutions and lenders from time to
time party hereto (the "Lenders"), WACHOVIA BANK, NATIONAL ASSOCIATION, in its
capacity as administrative agent for the Lenders (the "Administrative Agent"),
as issuing bank (the "Issuing Bank") and as swingline lender (the "Swingline
Lender"), SUNTRUST BANK, as syndication agent (the "Syndication Agent"), and
HARRIS NESBIT FINANCING, INC., BARCLAYS BANK PLC, and CITIBANK, N.A., as
co-documentation agents (the "Co-Documentation Agents"). All capitalized terms
used in this Amendment and not otherwise defined herein have the meanings
ascribed to such terms in the Credit Agreement (as defined below).

                             PRELIMINARY STATEMENT

                  The Borrower, the Administrative Agent, the Issuing Bank, the
Swingline Lender, the Syndication Agent, the Co-Documentation Agents, and the
Lenders are parties to that certain Revolving Credit Agreement dated as of May
16, 2005 (the "Credit Agreement").

                  The Borrower has requested that the Lenders amend the Credit
Agreement as set forth herein. The Lenders are agreeable to such request, upon
the conditions set forth herein.

                  NOW THEREFORE, in consideration of the premises and other
good and valuable consideration, the receipt and adequacy of which are hereby
acknowledged by the parties hereto, the Borrower, the Guarantor, the
Administrative Agent, the Issuing Bank, the Swingline Lender, the Syndication
Agent, the Co-Documentation Agents and the Lenders hereby agree as follows:

Section 1.        Amendments to Credit Agreement.

                  (a) Section 1.1 of the Credit Agreement is hereby amended by
replacing the definition of "Change in Control" in its entirety with the
following definition:

                           "Change in Control" shall mean (i) the failure of
                           Northern Border Partners to own, directly or
                           indirectly through one or more of its wholly owned
                           Subsidiaries, free and clear of all Liens, at least
                           50% of the partnership interests in Borrower, or
                           (ii) the failure of ONEOK, Inc. to own, directly or
                           indirectly, free and clear of all Liens, general
                           partner interests in Northern Border Partners and
                           the Intermediate Partnership such that the aggregate
                           voting rights of ONEOK, Inc. are greater than 50% of
                           the outstanding voting rights of all general
                           partners of Northern Border Partners and the
                           Intermediate Partnership.

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(b) Section 1.1 of the Credit Agreement is hereby further amended by replacing
the definition of "Northern Border Partners Credit Agreement" in its entirety
with the following definition:

                           "Northern Border Partners Credit Agreement" shall
                           mean that certain Amended and Restated Revolving
                           Credit Agreement, dated as of March 30, 2006, by
                           and among Northern Border Partners, the lenders from
                           time to time parties thereto, and SunTrust Bank, as
                           administrative agent, as amended, supplemented
                           restated or otherwise modified from time to time.

                  Section 2. No Obligation. Notwithstanding this Amendment, the
Lenders shall have no further obligation to modify the Credit Agreement as
amended by this Amendment and no further obligation of any kind shall be
inferred from this Amendment.

                  Section 3. Ratification. The Borrower hereby ratifies each of
its obligations under the Credit Agreement and the other Loan Documents to
which it is a party, and agrees and acknowledges that the Credit Agreement and
each of the other Loan Documents shall continue in full force and effect as
amended and modified by this Amendment. Nothing in this Amendment extinguishes,
novates or releases any right, claim, lien, security interest or entitlement of
any of the Lenders created by or contained in any of such documents, nor is the
Borrower released from any covenant, warranty or obligation created by or
contained therein except as expressly provided herein.

                  Section 4. Representations True; No Default. The Borrower
represents and warrants to the Administrative Agent and the Lenders that:

                  (a) this Amendment has been duly authorized, executed and
delivered on behalf of the Borrower. The Credit Agreement as amended hereby and
the Notes, together with each other Loan Document to which the Borrower is a
party, constitute valid and legally binding agreements of the Borrower
enforceable in accordance with their terms;

                  (b) the execution, delivery and performance by the Borrower
of this Amendment (i) does not require any consent or approval of, registration
or filing with, or any action by, any Governmental Authority, except those as
have been obtained or made and are in full force and effect, (ii) will not
violate any Requirements of Law applicable to the Borrower or any of its
Subsidiaries or any judgment, order or ruling of any Governmental Authority,
(iii) will not violate or result in a default under any indenture, agreement or
other instrument binding on the Borrower or any of its Subsidiaries or any of
its assets or give rise to a right thereunder to require any payment to be made
by the Borrower or any of its Subsidiaries, in each case other than violations,
defaults or rights which could not reasonably expected to result in a Material
Adverse Effect, and (iv) will not result in the creation or imposition of any
Lien on any asset of the Borrower or any of its Subsidiaries, except Liens (if
any) created under the Loan Documents;

                  (c) the representations and warranties of the Borrower
contained in Article IV of the Credit Agreement are true and correct in all
material respects on and as of the date hereof


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as though made on and as of the date hereof, except to the extent such
representations and warranties relate solely to an earlier date; and

                  (d) after giving effect to this Amendment, there has not
occurred and is continuing an Event of Default or any event which with notice
or lapse of time would become an Event of Default.

                  Section 5. Effectiveness. This Amendment shall become
effective when, and only when, (i) the Borrower and the Required Lenders shall
have executed a counterpart of this Amendment and the Administrative Agent
shall have received delivery of same, and (ii) the "NBPC Sale" (as such term is
defined in the Northern Border Partners Credit Agreement) has been consummated.
The execution, delivery and effectiveness of this Amendment shall not, except
as expressly provided herein, operate as a waiver of any right, power or remedy
of the Lenders under the Credit Agreement, nor constitute a waiver of any
provision of the Credit Agreement. This Amendment shall constitute a Loan
Document for all purposes of the Credit Agreement.

                  Section 6. Expenses. The Borrower agrees to pay on demand all
costs and expenses, if any (including, without limitation, reasonable counsel
fees and expenses), in connection with the negotiation, preparation and
enforcement (whether through negotiations, legal proceedings or otherwise) of
this Amendment, including, without limitation, reasonable counsel fees and
expenses in connection with the enforcement of rights under this Section.

                  Section 7. Miscellaneous Provisions.

                  (a) From and after the execution and delivery of this
Amendment, the Credit Agreement shall be deemed to be amended and modified as
herein provided, but except as so amended and modified the Credit Agreement,
the Notes and all other Loan Documents shall continue in full force and effect.

                  (b) The Credit Agreement and this Amendment shall be read and
construed as one and the same instrument.

                  (c) Any reference in any Loan Document to the Credit
Agreement shall be a reference to the Credit Agreement as amended by this
Amendment.

                  (d) This Amendment shall be construed in accordance with and
governed by the laws of the State of New York and of the United States of
America.

                  (e) This Amendment may be signed in any number of
counterparts and by different parties in separate counterparts, each of which
shall be deemed an original but all of which together shall constitute one and
the same instrument. Delivery of an executed counterpart of this Amendment by
facsimile transmission or by electronic mail in pdf form shall be as effective
as delivery of a manually executed counterpart hereof.

                  (f) The headings herein shall be accorded no significance in
interpreting this Amendment.


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                  Section 8. Binding Effect. The Amendment shall be binding
upon and inure to the benefit of the Borrower, the Administrative Agent, the
Issuing Bank, the Swingline Lender, the Co-Documentation Agents and the Lenders
and the successors and assigns of such parties. The Borrower shall not have the
right to assign its rights hereunder or any interest herein.

                  Section 9. Final Agreement of the Parties. This Amendment,
the Notes, the Credit Agreement and the other Loan Documents represent the
final agreement between the parties and may not be contradicted by evidence of
prior, contemporaneous or subsequent oral agreements of the parties. There are
no unwritten oral agreements between the parties.

                            [SIGNATURE PAGES FOLLOW]


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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
be duly executed by their respective authorized officers as of the day and year
first above written.



                              NORTHERN BORDER PIPELINE COMPANY

                              By: Northern Plains Natural Gas Company LLC,
                                  as Operator



                              By     /s/ Jerry L. Peters
                                -----------------------------------------------
                                 Name:  Jerry L. Peters
                                 Title:  Vice President, Finance and Treasurer




                              WACHOVIA BANK, NATIONAL ASSOCIATION
                              AS ADMINISTRATIVE AGENT, AS ISSUING BANK,
                              AS SWINGLINE LENDER AND AS A LENDER



                              By       /s/ Shannan Townsend
                                -----------------------------------------------
                                  Name:  Shannan Townsend
                                  Title:  Director

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                              SUNTRUST BANK
                              AS SYNDICATION AGENT AND AS A LENDER



                              By       /s/ Peter Panos
                                -----------------------------------------------
                              Name:  Peter Panos
                              Title:  Vice President

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                              HARRIS NESBITT FINANCING, INC.


                              By:      /s/ Cahal B. Carmody
                                -----------------------------------------------
                              Name:  Cahal B. Carmody
                              Title:  Vice President

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                              BARCLAYS BANK PLC


                              By:      /s/  Alison McGuigan
                                -----------------------------------------------
                              Name:  Alison McGuigan
                              Title:  Associate Director

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                              CITIBANK, N.A.


                              By:      /s/ Todd J. Mogil
                                -----------------------------------------------
                              Name:  Todd J. Mogil
                              Title:  Attorney-in-fact

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                              ROYAL BANK OF CANADA


                              By:      /s/  David A. McCluskey
                                -----------------------------------------------
                              Name:  David A. McCluskey
                              Title:  Authorized Signatory

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                              WELLS FARGO BANK, N.A.


                              By:      /s/ Tim Green
                                -----------------------------------------------
                              Name:  Tim Green
                              Title:  Assistant Vice President