FIRST SUPPLEMENTAL INDENTURE BY AND BETWEEN WPS RESOURCES CORPORATION AND U.S. BANK NATIONAL ASSOCIATION, AS TRUSTEE

FIRST SUPPLEMENTAL INDENTURE

BY AND BETWEEN

WPS RESOURCES CORPORATION

AND

U.S. BANK NATIONAL ASSOCIATION, AS TRUSTEE

_________________

Dated as of December 1, 2006

SUPPLEMENTAL TO

INDENTURE DATED AS OF NOVEMBER 13, 2006

6.11% Junior Subordinated Notes Due 2066

TABLE OF CONTENTS

FIRST SUPPLEMENTAL INDENTURE

        This FIRST SUPPLEMENTAL INDENTURE is made as of December 1, 2006 (the "First Supplemental Indenture") by and between WPS RESOURCES CORPORATION, a corporation duly organized and existing under the laws of the State of Wisconsin (the "Company"), and U.S. BANK NATIONAL ASSOCIATION, a national banking association duly organized and existing under the laws of the United States, as trustee (the "Trustee"), under the Indenture, dated as of November 13, 2006, by and between the Company and the Trustee (the "Base Indenture" and, together with this First Supplemental Indenture, the "Indenture").

RECITALS

         WHEREAS, the Company executed and delivered the Base Indenture to the Trustee to provide for the issuance from time to time of the Company’s unsecured subordinated debentures, notes or other evidences of indebtedness (the "Securities"), to be issued in one or more series as might be determined by the Company under the Base Indenture, in an unlimited aggregate principal amount which may be authenticated and delivered as provided in the Base Indenture;

         WHEREAS, pursuant to the terms of the Base Indenture, the Company desires to provide for the establishment of a series of its Securities, to be known as its 6.11% Junior Subordinated Notes Due 2066 (the "Junior Subordinated Notes"), the form and substance of the Junior Subordinated Notes and the terms, provisions and conditions thereof to be set forth as provided in the Base Indenture and this First Supplemental Indenture;

         WHEREAS, the Company desires that the Junior Subordinated Notes be originally issued on December 1, 2006, in an aggregate principal amount of $300,000,000, pursuant to the Indenture; and

         WHEREAS, the Company has requested that the Trustee execute and deliver this First Supplemental Indenture, and all requirements necessary to make this First Supplemental Indenture a valid instrument in accordance with its terms, and to make the Junior Subordinated Notes, when executed by the Company and authenticated and delivered by the Trustee, the valid obligations of the Company, have been performed, and the execution and delivery of this First Supplemental Indenture has been duly authorized in all respects;

AGREEMENT

         NOW, THEREFORE, in consideration of the purchase and acceptance of the Junior Subordinated Notes by the holders thereof, and for the purpose of setting forth, as provided in the Base Indenture, the form and substance of the Junior Subordinated Notes and the terms, provisions and conditions thereof, the Company covenants and agrees with the Trustee as follows:

ARTICLE I
DEFINITIONS

     1.1 Definition of Terms. For all purposes of this First Supplemental Indenture, except as otherwise expressly provided or unless the context otherwise requires:

        (a)  the terms not otherwise defined herein which are defined in the Base Indenture have the same meanings when used in this First Supplemental Indenture;

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

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

        (d)  the word "including" (and with correlative meaning "include") means including, without limiting the generality of, any description preceding such term;

        (e)  a reference to a Section or Article is to a Section or Article of this First Supplemental Indenture unless otherwise stated;

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

        (g)  the Article and Section headings herein and the Table of Contents are for convenience only and shall not affect the construction hereof;

        "Additional Interest" has the meaning specified in Section 2.4(a).

        "Administrative Action" means any judicial decision or any official administrative pronouncement, ruling, regulatory procedure, notice or announcement including any notice or announcement of intent to issue or adopt any administrative pronouncement, ruling, regulatory procedure or regulation.

        "Base Indenture" has the meaning specified in the Preamble to this First Supplemental Indenture.

        "Business Day" means any day that is not a Saturday, a Sunday, or a day on which banks in New York City are authorized or obligated by law or executive order to remain closed, or a day on which the Corporate Trust Office of the Trustee is closed for business.

        "Calculation Agent" means JPMorgan Chase Bank, N.A., or its successor appointed by the Company, acting as calculation agent.

        "Company" has the meaning specified in the Preamble to this First Supplemental Indenture.

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        "Comparable Treasury Issue" means, with respect to any Redemption Date, the United States Treasury security selected by the Calculation Agent as having a maturity comparable to the time period from the Redemption Date to December 1, 2016 that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities with a term to maturity comparable to such time period. If no United States Treasury security has a maturity which is within a period from three months before to three months after December 1, 2016, the two most closely corresponding United States Treasury securities shall be used as the Comparable Treasury Issue, and the Treasury Rate shall be interpolated or extrapolated on a straight-line basis, rounding to the nearest month using such securities.

        "Comparable Treasury Price" means, with respect to any Redemption Date, (A) the average, after excluding the highest and lowest such Reference Treasury Dealer Quotations, of up to five Reference Treasury Dealer Quotations for such Redemption Date, or (B) if the Calculation Agent obtains fewer than five such Reference Treasury Dealer Quotations, the average of all such Reference Treasury Dealer Quotations.

        "Fixed Interest Rate" has the meaning specified in Section 2.4(a).

        "Fixed Rate Period" has the meaning specified in Section 2.4(a).

        "Floating Interest Rate" has the meaning specified in Section 2.4(a).

        "Floating Rate Period" has the meaning specified in Section 2.4(a).

        "Indenture" has the meaning specified in the Preamble to this First Supplemental Indenture.

        "Interest Payment Date" has the meaning specified in Section 2.4(a).

        "Interest Rate" has the meaning specified in Section 2.4(a).

        "Junior Subordinated Notes" has the meaning specified in the Recitals to this First Supplemental Indenture.

        "LIBOR Business Day" means any Business Day on which dealings in deposits in U.S. dollars are transacted in the London Inter-Bank Market.

        "LIBOR Interest Determination Date" means the second LIBOR Business Day preceding each LIBOR Rate Reset Date.

        "LIBOR Rate Reset Date" means, subject to Section 2.4(b), March 1, June 1, September 1 and December 1 of each year, beginning March 1, 2017.

        "Make-Whole Amount" means an amount equal to the greater of (i) 100% of the principal amount of the Junior Subordinated Notes being redeemed or (ii) as determined by the Calculation Agent as of the Redemption Date, the sum of the present value of each scheduled payment of principal of and interest on the Junior Subordinated Notes from the Redemption Date to December 1, 2016 (assuming, solely for the purposes of this calculation, that the principal amount of the Junior Subordinated Notes to be redeemed was payable on December 1, 2016), discounted to the Redemption Date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at a discount rate equal to the Treasury Rate plus 25 basis points.

3

        "Optional Deferral Period" has the meaning specified in Section 4.1.

        "Rating Agency" means any nationally recognized statistical rating organization within the meaning of Rule 15c3-1 under the Exchange Act that publishes a rating for the Company as of the date of original issuance of the Junior Subordinated Notes.

        "Rating Agency Event" means the determination by the Company of a change by any Rating Agency in the equity credit criteria for securities such as the Junior Subordinated Notes resulting in a lower equity credit to the Company than the equity credit assigned by such Rating Agency to the Junior Subordinated Notes on the date of original issuance of the Junior Subordinated Notes.

        "Rating Agency Event Make-Whole Amount" means an amount equal to the greater of (i) 100% of the principal amount of the Junior Subordinated Notes being redeemed or (ii) as determined by the Calculation Agent as of the Redemption Date, the sum of the present value of each scheduled payment of principal of and interest on the Junior Subordinated Notes from the Redemption Date to December 1, 2016 (assuming, solely for the purposes of this calculation, that the principal amount of the Junior Subordinated Notes to be redeemed was payable on December 1, 2016), discounted to the Redemption Date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at a discount rate equal to the Treasury Rate plus 50 basis points.

        "Reference Treasury Dealer" means JPMorgan Chase Bank, N.A., Banc of America Securities LLC and up to three additional nationally recognized investment banking firms specified by the Company that are primary U.S. Government Securities dealers.

        "Reference Treasury Dealer Quotations" means, with respect to each Reference Treasury Dealer and any Redemption Date, the average, as determined by the Calculation Agent, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Calculation Agent by such Reference Treasury Dealer at 5:00 p.m., New York City time, on the third Business Day preceding such Redemption Date.

        "Regular Record Date" means (i) so long as the Junior Subordinated Notes remain in book-entry only form registered in the name of the Depositary or its nominee, the Business Day immediately preceding the applicable Interest Payment Date or (ii) at any time the Junior Subordinated Notes are not in book-entry only form registered in the name of the Depositary or its nominee, the fifteenth calendar day (whether or not a Business Day) immediately preceding the applicable Interest Payment Date.

        "Securities" has the meaning specified in the Recitals to this First Supplemental Indenture.

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        "Senior Indebtedness" means, with respect to the Company, (i) the principal of, premium, if any, and interest in respect of (A) indebtedness of the Company for money borrowed and (B) indebtedness evidenced by securities, debentures, bonds or other similar instruments issued by the Company; (ii) all capital lease obligations of the Company; (iii) all obligations of the Company issued or assumed as the deferred purchase price of property, all conditional sale obligations of the Company and all obligations of the Company under any title retention agreement (but excluding trade accounts payable arising in the ordinary course of business); (iv) all obligations of the Company for the reimbursement on any letter of credit, banker’s acceptance, security purchase facility or similar credit transaction; (v) all obligations of the type referred to in clauses (i) through (iv) of other Persons for the payment of which the Company is responsible or liable as obligor, guarantor or otherwise; and (vi) all obligations of the type referred to in clauses (i) through (v) of other Persons secured by any lien on any property or asset of the Company (whether or not such obligation is assumed by the Company); except in each case for (1) any such indebtedness that is by its terms subordinated to or pari passu with the Junior Subordinated Notes, as the case may be, (2) any indebtedness from the Company to any Affiliate of the Company and (3) any accrued liabilities of the Company arising in the ordinary course of business.

        "Tax Event" means the receipt by the Company of an opinion of counsel experienced in tax matters to the effect that, as a result of (a) any amendment to, clarification of, or change, including any announced prospective change, in the laws or treaties of the United States or any of its political subdivisions or taxing authorities, or any regulations under those laws or treaties, (b) an Administrative Action or (c) any amendment to, clarification of, or change in the official position or the interpretation of any Administrative Action or any interpretation or pronouncement that provides for a position with respect to an Administrative Action that differs from the previously generally accepted position, in each case by any legislative body, court, governmental authority or regulatory body, regardless of the time or manner in which that amendment, clarification or change is introduced or made known, which amendment, clarification, or change is effective or the Administrative Action is taken or issued, or interpretation or pronouncement is issued after the date of original issuance of the Junior Subordinated Notes, there is more than an insubstantial risk that interest payable by the Company on the Junior Subordinated Notes is not deductible, or within 90 days of the date of such opinion would not be deductible, in whole or in part, by the Company for United States federal income tax purposes.

        "Tax Event Make-Whole Amount" means an amount equal to the greater of (i) 100% of the principal amount of the Junior Subordinated Notes being redeemed or (ii) as determined by the Calculation Agent as of the Redemption Date, the sum of the present value of each scheduled payment of principal of and interest on the Junior Subordinated Notes from the Redemption Date to December 1, 2016 (assuming, solely for the purposes of this calculation, that the principal amount of the Junior Subordinated Notes to be redeemed was payable on December 1, 2016), discounted to the Redemption Date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at a discount rate equal to the Treasury Rate plus 50 basis points.

        "Telerate Page 3750" means the display designated as "Telerate page 3750" on Moneyline Telerate, Inc. (or such other page as may replace "Telerate page 3750" on such service) or such other service displaying the London Inter-Bank offered rates of major banks, as may replace Moneyline Telerate, Inc.

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        "Three-Month LIBOR Rate" means the rate determined in accordance with the following provisions:

        (1)  On the LIBOR Interest Determination Date, the Calculation Agent will determine the Three-Month LIBOR Rate which shall be the rate for deposits in U.S. dollars having a three-month maturity which appears on the Telerate Page 3750 as of 11:00 a.m., London time, on the LIBOR Interest Determination Date.

        (2)  If no rate appears on Telerate Page 3750 on the LIBOR Interest Determination Date, the Calculation Agent will request the principal London offices of four major reference banks in the London Inter-Bank Market to provide it with their offered quotations for deposits in U.S. dollars for the period of three months, commencing on the applicable LIBOR Rate Reset Date, to prime banks in the London Inter-Bank Market at approximately 11:00 a.m., London time, on that LIBOR Interest Determination Date and in a principal amount that is representative for a single transaction in U.S. dollars in that market at that time. If at least two quotations are provided, then the Three-Month LIBOR Rate will be the average (rounded, if necessary, to the nearest one hundredth (0.01) of a percent) of those quotations. If fewer than two quotations are provided, then the Three-Month LIBOR Rate will be the average (rounded, if necessary, to the nearest one hundredth (0.01) of a percent) of the rates quoted at approximately 11:00 a.m., New York City time, on the LIBOR Interest Determination Date by three major banks in New York City selected by the Calculation Agent for loans in U.S. dollars to leading European banks, having a three-month maturity and in a principal amount that is representative for a single transaction in U.S. dollars in that market at that time. If the banks selected by the Calculation Agent are not providing quotations in the manner described by this paragraph, the rate for the quarterly interest period following the LIBOR Interest Determination Date will be the rate in effect on that LIBOR Interest Determination Date.

        "Treasury Rate" means (i) the yield, under the heading which represents the average for the immediately preceding week, appearing in the most recently published statistical release designated "H.15(519)" or any successor publication which is published weekly by the Federal Reserve and which establishes yields on actively traded United States Treasury securities adjusted to constant maturity under the caption "Treasury Constant Maturities," for the maturity corresponding to the time period from the Redemption Date to December 1, 2016, (if no maturity is within three months before or after such time period, yields for the two published maturities most closely corresponding to such time period shall be determined by the Calculation Agent and the Treasury Rate shall be interpolated or extrapolated from such yields on a straight-line basis, rounding to the nearest month) or (ii) if such release (or any successor release) is not published during the week preceding the calculation date or does not contain such yields, the rate per annum equal to the semi-annual equivalent yield to maturity of the Comparable Treasury Issue, calculated using a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for such Redemption Date. The Treasury Rate shall be calculated on the third Business Day preceding the Redemption Date.

6

        "Trustee" has the meaning specified in the Preamble to this First Supplemental Indenture.

ARTICLE II
GENERAL TERMS AND CONDITIONS OF THE JUNIOR SUBORDINATED NOTES

     2.1 Designation and Principal Amount; Original Issuance; Further Issues.

        (a)  There is hereby authorized a new series of Securities, to be designated the "6.11% Junior Subordinated Notes Due 2066." The aggregate principal amount of Securities of this series shall not be limited.

        (b)  Junior Subordinated Notes in the initial aggregate principal amount of $300,000,000 may be executed by the Company and delivered to the Trustee for authentication by the Trustee, together with a Company Order for the authentication and delivery of such Junior Subordinated Notes, and the Trustee shall thereupon authenticate and make such Junior Subordinated Notes available for delivery in accordance with the Company Order.

        (c)