4D
                                  THIRTY-THIRD
                                       

                             SUPPLEMENTAL INDENTURE


                                      FROM




                            WISCONSIN PUBLIC SERVICE
                                  CORPORATION



                                       TO




               FIRSTAR BANK MILWAUKEE, N.A., NATIONAL ASSOCIATION
                      (SUCCESSOR TO FIRSTAR TRUST COMPANY,
                FORMERLY KNOWN AS FIRST WISCONSIN TRUST COMPANY)
                                    TRUSTEE


                               -----------------


                          DATED AS OF DECEMBER 1, 1998


                               -----------------


                                  SUPPLEMENTAL
                                       TO
                        FIRST MORTGAGE AND DEED OF TRUST
                          DATED AS OF JANUARY 1, 1941

                                       


                       WISCONSIN PUBLIC SERVICE CORPORATION
                       THIRTY-THIRD SUPPLEMENTAL INDENTURE

                           Dated as of December 1, 1998

                                TABLE OF CONTENTS

                                -----------------



                                                                                 PAGE
                                                                                 ----
                                                                              
     Parties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1
     Recitals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1
     Form of Bond of Collateral Series A . . . . . . . . . . . . . . . . . . . . .  3
     Form of Trustee's Certificate . . . . . . . . . . . . . . . . . . . . . . . .  5
     Form of Prepayment Record . . . . . . . . . . . . . . . . . . . . . . . . . .  8
     Further Recitals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  8

                                     ARTICLE I
                      FORM OF EXECUTION OF BONDS OF NEW SERIES

     Sec. 1.01      Terms of bonds of new series . . . . . . . . . . . . . . . . .   9
     Sec. 1.02      Limitation of new series to $50,000,000. . . . . . . . . . . .   9
     Sec. 1.03      Optional redemption of bonds of new series by Company. . . . .   9
     Sec. 1.04      Notice of, and selection of bonds of new series for,
                    redemption . . . . . . . . . . . . . . . . . . . . . . . . . .  10
     Sec. 1.05      Redemption in event of default under section 6.01 of the
                    Senior Indenture . . . . . . . . . . . . . . . . . . . . . . .  11
     Sec. 1.06      Partial redemption and payments of redemption price without
                    presentation of bonds and new series . . . . . . . . . . . . .  11
     Sec. 1.07      Company not obligated to make any transfer of bonds of new
                    series for fifteen days before any interest payment date . . .  12
     Sec. 1.08      Charges for transfer of bonds of new series. . . . . . . . . .  12
     Sec. 1.09      Bonds of new series may be signed by facsimile signatures of
                    Company officers . . . . . . . . . . . . . . . . . . . . . . .  12
     Sec. 1.10      Payment dates falling on Saturday, Sunday or legal
                    holiday. . . . . . . . . . . . . . . . . . . . . . . . . . . .  12
     Sec. 1.11      Bonds of new series redeemed or paid not reissuable, but may
                    be basis for issuance of bonds of different series,
                    credits or cash withdrawals. . . . . . . . . . . . . . . . . .  12

                                     ARTICLE II
                                CONFIRMATION OF LIEN

     Sec. 2.01      Granting clauses and habendum. . . . . . . . . . . . . . . . .  12

                                       i



                                   ARTICLE III
                       PARTICULAR COVENANTS OF THE COMPANY

     Sec. 3.01      Duly authorized by law to execute and deliver Supplemental
                    Indenture and issue bonds. . . . . . . . . . . . . . . . . . .  13
     Sec. 3.02      Covenant of lawful possession, right to mortgage
                    property and to maintain lien of Indenture.. . . . . . . . . .  13
     Sec. 3.03      Payment of principal and interest. . . . . . . . . . . . . . .  13
     Sec. 3.04      Nonliability of Trustee. . . . . . . . . . . . . . . . . . . .  14

                                     ARTICLE IV
                                   MISCELLANEOUS

     Sec. 4.01      Recitals not made by Trustee.  No representations made by
                    Trustee.  Trust accepted subject to terms and conditions of
                    Indenture. . . . . . . . . . . . . . . . . . . . . . . . . . .  14
     Sec. 4.02      Supplemental Indenture to be construed as part of Indenture. .  14
     Sec. 4.03(a)   References to either party to Supplemental Indenture
                    includes successors or assigns . . . . . . . . . . . . . . . .  14
              (b)   Table of contents and descriptive headings of articles not
                    to affect meaning. . . . . . . . . . . . . . . . . . . . . . .  14
     Sec. 4.04(a)   Trust Indenture Act requirements control . . . . . . . . . . .  14
              (b)   Severability of Supplemental Indenture provisions and
                    bond provisions. . . . . . . . . . . . . . . . . . . . . . . .  14
     Sec. 4.05      Provisions for execution in counterparts . . . . . . . . . . .  15
     Sec. 4.06      Supplemental Indenture effective on execution and
                    delivery . . . . . . . . . . . . . . . . . . . . . . . . . . .  15
     Sec. 4.07      Names and addresses of debtor and secured party. . . . . . . .  15


                                       ii



          THIRTY-THIRD SUPPLEMENTAL INDENTURE, made as of the 1st day of 
December, 1998, by and between WISCONSIN PUBLIC SERVICE CORPORATION, a 
corporation duly organized and existing under and by virtue of the laws of 
the State of Wisconsin, having its principal office in the City of Green Bay 
in said State (hereinafter sometimes called the "Company"), party of the 
first part, and FIRSTAR BANK MILWAUKEE, N.A., NATIONAL ASSOCIATION (successor 
to Firstar Trust Company, formerly known as First Wisconsin Trust Company), a 
national banking association duly organized and existing under and by virtue 
of the laws of the United States, having its principal office in the City of 
Milwaukee in the State of Wisconsin, as Trustee (hereinafter sometimes called 
the "Trustee"), party of the second part.

          WHEREAS, the Company has heretofore executed and delivered to the 
predecessor of the Trustee its First Mortgage and Deed of Trust made as of 
January 1, 1941 (hereinafter referred to as the "1941 Mortgage") and has 
heretofore executed and delivered to the predecessor of the Trustee 
supplemental indentures dated and hereinafter referred to as follows:



        SUPPLEMENTAL INDENTURE               
             DATED (AS OF)                    HEREINAFTER REFERRED TO AS
        ----------------------                --------------------------
                                    
 November 1, 1947 . . . . . . . . . .  First Supplemental Indenture*
 August 1, 1948 . . . . . . . . . . .  Second Supplemental Indenture
 September 1, 1949. . . . . . . . . .  Third Supplemental Indenture
 November 1, 1950 . . . . . . . . . .  Fourth Supplemental Indenture*
 May 1, 1953. . . . . . . . . . . . .  Fifth Supplemental Indenture*
 January 1, 1954. . . . . . . . . . .  Sixth Supplemental Indenture
 October 1, 1954. . . . . . . . . . .  Seventh Supplemental Indenture
 December 1, 1957 . . . . . . . . . .  Eighth Supplemental Indenture
 November 1, 1959 . . . . . . . . . .  Ninth Supplemental Indenture
 October 1, 1963. . . . . . . . . . .  Tenth Supplemental Indenture
 June 1, 1964 . . . . . . . . . . . .  Eleventh Supplemental Indenture
 November 1, 1967 . . . . . . . . . .  Twelfth Supplemental Indenture
 April 1, 1969. . . . . . . . . . . .  Thirteenth Supplemental Indenture
 August 1, 1970 . . . . . . . . . . .  Fourteenth Supplemental Indenture
 May 1, 1971. . . . . . . . . . . . .  Fifteenth Supplemental Indenture
 August 1, 1973 . . . . . . . . . . .  Sixteenth Supplemental Indenture*
 September 1, 1973. . . . . . . . . .  Seventeenth Supplemental Indenture
 October 1, 1975. . . . . . . . . . .  Eighteenth Supplemental Indenture
 February 1, 1977 . . . . . . . . . .  Nineteenth Supplemental Indenture
 July 15, 1980. . . . . . . . . . . .  Twentieth Supplemental Indenture
 December 1, 1980 . . . . . . . . . .  Twenty-First Supplemental Indenture*
 April 1, 1981. . . . . . . . . . . .  Twenty-Second Supplemental Indenture
 February 1, 1984 . . . . . . . . . .  Twenty-Third Supplemental Indenture
 March 15, 1984 . . . . . . . . . . .  Twenty-Fourth Supplemental Indenture
 October 1, 1985. . . . . . . . . . .  Twenty-Fifth Supplemental Indenture

                                       


        SUPPLEMENTAL INDENTURE               
             DATED (AS OF)                    HEREINAFTER REFERRED TO AS
        ----------------------                --------------------------
                                    
 December 1, 1987 . . . . . . . . . .  Twenty-Sixth Supplemental Indenture*
 September 1, 1991. . . . . . . . . .  Twenty-Seventh Supplemental Indenture
 July 1, 1992 . . . . . . . . . . . .  Twenty-Eighth Supplemental Indenture
 October 1, 1992. . . . . . . . . . .  Twenty-Ninth Supplemental Indenture
 February 1, 1993 . . . . . . . . . .  Thirtieth Supplemental Indenture
 July 1, 1993 . . . . . . . . . . . .  Thirty-First Supplemental Indenture
 November 1, 1993 . . . . . . . . . .  Thirty-Second Supplemental Indenture



- ------------------

*Includes amendments to or modifications of certain provisions of the 1941
Mortgage.

(said 1941 Mortgage, as supplemented, amended or modified by the aforesaid 
Supplemental Indentures, being hereinafter referred to as the "Indenture", 
except as such term is differently defined and used in and for the purposes 
of the Form of Bond of Collateral Series A and the Form of Trustee's 
Certificate hereinafter set forth), whereby the Company granted, bargained, 
sold, warranted, released, conveyed, assigned, transferred, mortgaged, 
pledged, set over and confirmed unto the Trustee, and to its respective 
successors in trust, upon the terms, conditions and trusts therein set forth, 
all the property as therein described, real, personal and mixed, then owned 
or thereafter acquired by the Company, with certain exceptions as in the 
granting clauses and definitions of the Indenture set forth, to be held by 
the Trustee in trust, under the terms and subject to the conditions of the 
Indenture, as security for the bonds of the Company issued and to be issued 
thereunder in accordance with the provisions of the Indenture; and

          WHEREAS, Section 2.01 of the 1941 Mortgage provides that bonds may 
be issued thereunder in one or more series, each series to have such 
distinctive designation as the Board of Directors of the Company may select 
for such series; and

          WHEREAS, the Company has heretofore issued and there are now 
outstanding, in accordance with the provisions of the 1941 Mortgage and said 
Supplemental Indentures bonds of several series designated "First Mortgage 
Bonds, 8.80% Series due September 1, 2021", "First Mortgage Bonds, 6c% Series 
due October 1, 2005", "First Mortgage Bonds, 7.30% Series due October 1, 
2002", "First Mortgage Bonds, 6.80% Series due February 1, 2003", "First 
Mortgage Bonds, 7c% Series Due July 1, 2023" and First Mortgage Bonds Due 
February 1, 2013; and

          WHEREAS, the Company has agreed to issue $50,000,000 in aggregate 
principal amount of Senior Notes, 6.08% Series Due December 1, 2028 (the 
"Related Securities") pursuant to an Indenture, dated as of December 1, 1998, 
between the Company and Firstar Bank Milwaukee, N.A., as trustee (the "Senior 
Trustee"); and

          WHEREAS, in order to secure the Company's obligations to pay 
principal, premium, if any, and interest on the Related Securities, the 
Company is desirous of providing 

                                       2


for the issuance under the Indenture of bonds of a new series designated as 
"First Mortgage Bonds, Collateral Series A", in an aggregate principal amount 
of not more than $50,000,000, the bonds of said series to be issued as 
registered bonds without coupons in any denominations that the Company may 
from time to time execute and deliver, the bonds of said series, the 
Trustee's Certificate, and the Form of Prepayment Record to be substantially 
in the tenor following:
                                       
                    (Form of Bond of Collateral Series A)

                    WISCONSIN PUBLIC SERVICE CORPORATION


             (Incorporated under the laws of the State of Wisconsin)
                     First Mortgage Bond, Collateral Series A
No._____________                                            $___________

THE FIRST MORTGAGE BONDS, COLLATERAL SERIES A (HEREINAFTER, "COLLATERAL 
BONDS"), REPRESENTED BY THIS CERTIFICATE ARE BEING ISSUED AND DELIVERED BY 
THE COMPANY TO FIRSTAR BANK MILWAUKEE, N.A., NATIONAL ASSOCIATION, AS TRUSTEE 
(IN SUCH CAPACITY, THE "SENIOR TRUSTEE") UNDER AN INDENTURE, DATED AS OF 
DECEMBER 1, 1998, BETWEEN THE COMPANY AND THE SENIOR TRUSTEE, AS SUPPLEMENTED 
BY THE FIRST SUPPLEMENTAL INDENTURE THERETO DATED AS OF DECEMBER 1, 1998 (AS 
SO SUPPLEMENTED, THE "SENIOR INDENTURE").  THE COLLATERAL BONDS ARE TO BE 
HELD IN TRUST AS COLLATERAL FOR THE BENEFIT OF THE HOLDERS OF $50,000,000 
AGGREGATE PRINCIPAL AMOUNT OF SENIOR NOTES, 6.08% SERIES DUE DECEMBER 1, 2028 
(THE "RELATED SECURITIES") ISSUED PURSUANT TO THE SENIOR INDENTURE.

THE COLLATERAL BONDS MAY NOT BE SOLD OR OTHERWISE TRANSFERRED (EXCEPT TO A 
SUCCESSOR SENIOR TRUSTEE) UNTIL THE EARLIER OF THE RELEASE DATE (AS DEFINED 
BELOW) OR THE PRIOR RETIREMENT OF THE RELATED SECURITIES THROUGH REDEMPTION, 
REPURCHASE OR OTHERWISE.

THE COMPANY SHALL MAKE PAYMENTS OF THE PRINCIPAL OF, AND PREMIUM, IF ANY, AND 
INTEREST ON, THE COLLATERAL BONDS, TO THE SENIOR TRUSTEE, WHICH PAYMENTS 
SHALL BE APPLIED BY THE SENIOR TRUSTEE TO THE SATISFACTION OF OBLIGATIONS ON 
THE RELATED SECURITIES.

THE MATURITY DATE SPECIFIED ABOVE IS ALSO THE MATURITY DATE OF THE RELATED 
SECURITIES.

          WISCONSIN PUBLIC SERVICE CORPORATION, a corporation organized and 
existing under the laws of the State of Wisconsin (hereinafter called the 
Company), for value received, hereby promises to pay to FIRSTAR BANK 
MILWAUKEE, N.A., NATIONAL 

                                       3



ASSOCIATION, as trustee for the benefit of the holders of Related Securities, 
or registered assigns (in such capacity, the "Senior Trustee"), on the 1st 
day of December, 2028, the sum of _____________________ DOLLARS 
($___________) in lawful money of the United States of America, and to pay 
interest thereon from the date hereof at the rate of six and eight hundredths 
per cent (6.08%) per annum, in like money, until the principal hereof becomes 
due and payable, said interest being payable on the 1st day of June and on 
the 1st day of December in each year commencing June 1, 1999.  The principal 
and interest so payable on any June 1 or December 1 will be paid to the 
person or entity in whose name this bond is registered, at the address 
thereof as it appears on the Company's books for registration and 
registration of transfer.

          The provisions of this bond are continued on the reverse hereof or 
attached pages and such continued provisions shall for all purposes have the 
same effect as though fully set forth at this place.

          This bond shall not be valid or become obligatory for any purpose 
unless and until Firstar Bank Milwaukee, N.A., National Association 
(successor to First Wisconsin Trust Company), as Trustee under the Indenture, 
or its successors thereunder, shall have signed the certificate of 
authentication endorsed hereon.

          IN WITNESS WHEREOF, WISCONSIN PUBLIC SERVICE CORPORATION has caused 
this bond to be signed in its name by the manual or facsimile signature of 
its President or a Vice President and its corporate seal or a facsimile 
thereof to be hereto affixed and attested by the manual or facsimile 
signature of its Secretary or an Assistant Secretary.

Dated as of:


 
                                        WISCONSIN PUBLIC SERVICE CORPORATION,



                                        By:
                                           ------------------------------------
                                                  ______ President
Attest:


- -----------------------------
____________ Secretary

                                       4


                        (Form of Trustee's Certificate)

          This bond is one of the bonds of the series designated therein, 
described in the within mentioned Indenture and Supplemental Indenture.



                               FIRSTAR BANK MILWAUKEE, N.A.,
                                 NATIONAL ASSOCIATION
                                   As Trustee


                              By:
                                 ---------------------------------------
                                        Authorized Signature

                                       
         (TEXT APPEARING ON REVERSE SIDE OF BOND OR ATTACHED PAGES)

          This bond is one of a duly authorized issue of bonds of the 
Company, known as its First Mortgage Bonds, of the series and designation 
indicated on the face hereof, which issue of bonds consists, or may consist, 
of several series of varying denominations, dates and tenors, all issued and 
to be issued under and equally secured (except in so far as a sinking fund, 
or similar fund, established in accordance with the provisions of the 
Indenture, may afford additional security for the bonds of any specific 
series) by a First Mortgage and Deed of Trust (herein called the "Indenture") 
dated as of January 1, 1941, executed by the Company to First Wisconsin Trust 
Company (subsequently succeeded by Firstar Bank Milwaukee, National 
Association, herein called the Trustee), as Trustee, to which Indenture and 
all instruments supplemental thereto reference is hereby made for a 
description of the property mortgaged and pledged, the nature and extent of 
the security, the rights of the holders of the bonds as to such security, and 
the terms and conditions upon which the bonds may be issued under the 
Indenture and any instruments supplemental thereto and are secured. The 
principal hereof may be declared or may become due on the conditions, in the 
manner and at the time set forth in the Indenture, upon the happening of a 
completed default as in the Indenture provided.  This bond is one of a series 
created by a Supplemental Indenture (herein called the "Supplemental 
Indenture") dated as of December 1, 1998, between the Company and the 
Trustee, which is supplemental to the Indenture.

          The Senior Trustee has agreed pursuant to the Senior Indenture to 
hold the Bonds of this Series as collateral for the benefit of the holders of 
the Related Securities under all circumstances and not to transfer (except to 
a successor trustee) such Bonds until the earlier of the Release Date or the 
prior retirement of the Related Securities through redemption, repurchase or 
otherwise.  "Release Date" means the date on which all First Mortgage Bonds 
of the Company issued and outstanding under the Indenture, other than the 
Bonds of this Series and other Bonds pledged as security for Securities 
issued under the Senior Indenture (collectively "Collateral Bonds"), have 
been retired (at, before or after the maturity thereof) 

                                       5


through payment, redemption or otherwise, provided that no default or event 
of default has occurred and is continuing under the Senior Indenture.  On the 
Release Date, the Senior Trustee shall deliver to the Company for 
cancellation all Collateral Bonds, and the Company shall cause the Senior 
Trustee to provide notice to all holders of Related Securities of the 
occurrence of the Release Date.  As a result, on the Release Date, the Bonds 
of this Series shall cease to secure the Related Securities. Following the 
Release Date, the Company shall cause the Indenture to be discharged, and the 
Company shall not issue any additional Collateral Bonds thereunder, and from 
and after the Release Date, the Company's obligations in respect of the 
Collateral Bonds shall be satisfied and discharged.

          With the consent of the Company and to the extent permitted by and 
as provided in the Indenture and/or any instruments supplemental thereto, the 
rights and obligations of the Company and/or of the holders of the bonds, 
and/or terms and provisions of the Indenture and/or of any instruments 
supplemental thereto may be modified or altered by consent of the holders of 
at least seventy percent (70%) in principal amount of the bonds then 
outstanding under the Indenture and any instruments supplemental thereto 
(excluding bonds challenged and disqualified from voting by reason of the 
interest of the Company or of certain related persons therein as provided in 
the Indenture); provided that no such modification or alteration shall permit 
the extension of the maturity of the principal of this bond or the reduction 
in the rate of interest hereon or any other modification in the terms of 
payment of such principal or interest or the taking of certain other action 
as more fully set forth in the Indenture without the consent of the holder 
hereof.

          The Company and the Trustee may deem and treat the person in whose 
name this bond is registered as the absolute owner hereof for the purpose of 
receiving payment of or on account of the principal hereof and interest 
hereon and for all other purposes, and shall not be affected by any notice to 
the contrary.

          The bonds of this Series are subject to redemption, prior to 
maturity, at the option of the Company in whole at any time or in part from 
time to time, upon payment of a redemption price equal to the greater of (i) 
100% of the principal amount of the bonds to be redeemed or (ii) the sum of 
the present values of the remaining scheduled payments of principal and 
interest thereon discounted to the redemption date on a semiannual basis 
(assuming a 360 day year consisting of twelve 30-day months) at the Treasury 
Yield (as defined in the Supplemental Indenture) plus two-tenths of one 
percent (.20%), plus in each case accrued interest thereon to the redemption 
date, all subject to the conditions and as more fully set forth in the 
Indenture and the Supplemental Indenture.

          Notice of any such redemption shall be hand delivered or mailed not 
less than thirty (30) days prior to the redemption date to the registered 
owner of the bonds so to be redeemed, at its address as the same shall appear 
on the Company's books for registration and registration of transfer, all 
subject to the conditions and as more fully set forth in the Indenture and in 
the Supplemental Indenture, except that no newspaper publication shall be 
required.

                                       6


          In the event that an event of default under Section 6.01 of the 
Senior Indenture has occurred and is continuing, and the Senior Trustee has 
declared the principal of all of the Related Securities then outstanding 
immediately due and payable (or such principal has become ipso facto 
immediately due and payable) under Section 6.02 of the Senior Indenture, then 
the Company shall call for redemption and redeem all of the bonds of this 
series then outstanding at a price equal to 100% of the principal amount 
thereof, together with accrued interest thereon to the redemption date.  The 
redemption date shall be the accelerated maturity date of the Related 
Securities, and no prior notice of such redemption to the Trustee or the 
Senior Trustee shall be required.

          This bond is nontransferable except to the Senior Trustee and 
successor trustees thereto.  To the extent that it is transferable, it is 
transferable by the registered owner hereof in person or by attorney duly 
authorized in writing, on books of the Company to be kept for that purpose at 
the principal office of the Trustee at Milwaukee, Wisconsin, upon surrender 
hereof for cancellation at said office and upon presentation of a written 
instrument of transfer duly executed.  Thereupon the Company shall issue in 
the name of the transferee, and the Trustee shall authenticate and deliver, a 
new registered bond or bonds without coupons of the same maturity and 
interest rate and of equal aggregate principal amount.  Any such transfer 
shall be subject to the terms and conditions specified in the Indenture and 
the Supplemental Indenture.

          No recourse shall be had for the payment of principal of, premium, 
if any, or interest on this bond, or any part thereof, or of any claim based 
hereon or in respect hereof or of the Indenture or any instrument 
supplemental thereto, against any incorporator, or any past, present or 
future stockholder, officer or director of the Company or of any predecessor 
or successor corporation, either directly or through the Company, or through 
any such predecessor or successor corporation, or through any receiver or a 
trustee in bankruptcy, whether by virtue of any constitution, statute or rule 
of law or by the enforcement of any assessment or penalty or otherwise, all 
such liability being, by the acceptance hereof and as a part of the 
consideration for the issue hereof, expressly waived and released, as more 
fully provided in the Indenture.

                               (END OF TEXT OF BOND)

                                       7


                                       
                         (Form of Prepayment Record)

                               PREPAYMENT RECORD

                     PRINCIPAL AMOUNT OF BOND $__________

                     DATE OF MATURITY:  December 1, 2028



        PREPAYMENTS ON PRINCIPAL
        ------------------------
                                            BALANCE          SIGNATURE OF  AUTHORIZED
       AMOUNT               DATE          OUTSTANDING           OFFICER AND TITLE
       ------               ----          -----------           -----------------
                                                    





and

          WHEREAS, the 1941 Mortgage provides that the Company and the 
Trustee may enter into indentures supplemental thereto for the purposes, 
among others, of providing the terms and conditions of the issue of the bonds 
of any new series; and

          WHEREAS, the Company is presently engaged within the States of 
Wisconsin and Michigan in transmitting, conveying, distributing, supplying 
and serving electricity and gas and intends that this Supplemental Indenture 
shall be received for record and for filing in the appropriate public offices 
of said States or of any other jurisdiction in which there may be located 
from time to time properties intended to be subject to the lien of the 
Indenture in the manner and with the effect provided by their respective laws 
in respect to mortgages by, and security interests in existing and hereafter 
acquired properties of, a corporation so engaged; and

          WHEREAS, the execution and delivery of this Supplemental Indenture 
and the issue of bonds as in this Supplemental Indenture and the Indenture 
provided have been duly authorized by a resolution adopted by the Board of 
Directors of the Company; and

          WHEREAS, all things necessary to make the bonds of Collateral 
Series A, when duly issued and executed by the Company, and authenticated and 
delivered by the Trustee, valid, binding and legal obligations of the 
Company, and to make the Indenture and this Supplemental Indenture valid, 
binding and legal instruments for the security thereof, have been done and 
performed and the issue of said bonds, as in this Supplemental Indenture and 
the Indenture provided, has been in all respects duly authorized;

     NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH:  Wisconsin 
Public Service Corporation, in consideration of the premises and of one 
dollar to it duly paid by the Trustee at or before the ensealing and delivery 
of these presents, the receipt whereof is hereby acknowledged, does hereby 
covenant and agree to and with Firstar Bank Milwaukee, National Association, 
as Trustee, as follows:

                                       8

                                   ARTICLE I.

                     FORM AND EXECUTION OF BONDS OF NEW SERIES

          SECTION 1.01.       There is hereby created, for issuance under the 
Indenture on the date of authentication and delivery of the Related 
Securities, a series of bonds designated as Collateral Series A (herein 
sometimes referred to as the bonds of Collateral Series A), each of which 
shall bear the descriptive title "First Mortgage Bond, Collateral Series A".  
The bonds of said series shall be issued only in the form of registered bonds 
without coupons and shall be substantially of the tenor and purport, and in 
the form, hereinbefore recited.  The bonds of said series shall mature on 
December 1, 2028, and shall be issued in any denominations that the Company 
may execute and deliver.  The bonds of said series shall bear interest at the 
rate of six and eight hundredths percent (6.08%) per annum, payable 
semiannually on June 1 and December 1 of each year commencing June 1, 1999.  
Bonds of said series issued prior to June 1, 1999 shall be dated as of 
December 1, 1998 and bonds of said series issued on and after June 1, 1999 
shall be dated as provided in Section 2.09 of the 1941 Mortgage.  Principal 
and interest will be payable to the registered owner of the bonds of said 
series, and at the address thereof, appearing on the Company's books for 
registration and registration of transfer.  Said bonds will be 
nontransferable except to the Senior Trustee and successors thereto, if any.

          SECTION 1.02.       The aggregate principal amount of all bonds of 
Collateral Series A which may at any time be certified, issued and 
outstanding shall be limited to $50,000,000, and bonds of said series may be 
executed, authenticated, delivered and issued hereunder from time to time 
subject to the restrictions and provisions contained in this Supplemental 
Indenture and in the 1941 Mortgage.

          SECTION 1.03.       The bonds of Collateral Series A are subject to 
redemption prior to maturity at the option of the Company, in whole at any 
time or in part from time to time, at a redemption price equal to the greater 
of (i) 100% of their principal amount or (ii) the sum of the present values 
of the remaining scheduled payments of principal and interest thereon 
discounted to the date of redemption on a semiannual basis (assuming a 360 
day year consisting of twelve 30-day months) at the Treasury Yield (as 
hereinafter defined) plus two-tenths of one percent (.20%), plus in each case 
accrued interest to the date of redemption.  The redemption price shall be 
set forth in an Officers' Certificate delivered to the Trustee on or before 
the redemption date.

          "Treasury Yield" means, with respect to any redemption date, the 
rate per annum equal to the semiannual equivalent yield to maturity of the 
Comparable Treasury Issue, assuming 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.

          "Comparable Treasury Issue" means the United States Treasury 
security selected by an Independent Investment Banker as having a maturity 
comparable to the remaining term of the bonds of Collateral Series A that 
would be utilized, at the time of 

                                       9


selection and in accordance with customary financial practice, in pricing new 
issues of corporate debt securities of comparable maturity to the remaining 
term of the bonds of Collateral Series A.  "Independent Investment Banker" 
means Salomon Smith Barney Inc. or, if such firm is unwilling or unable to 
select the Comparable Treasury Issue, one of the remaining Reference Treasury 
Dealers appointed by the Trustee after consultation with the Company.

          "Comparable Treasury Price" means, with respect to any redemption 
date, (i) the average of the bid and asked prices for the Comparable Treasury 
Issue (expressed in each case as a percentage of its principal amount) on the 
third business day preceding such redemption date, as set forth in the daily 
statistical release (or any successor release) published by the Federal 
Reserve Bank of New York and designated "Composite 3:30 p.m. Quotations for 
U.S. Government Securities" or (ii) if such release (or any successor 
release) is not published or does not contain such prices on such business 
day, (A) the average of the Reference Treasury Dealer Quotations for such 
redemption date, after excluding the highest and lowest such Referenced 
Treasury Dealer Quotations for such redemption date or (B) if the Trustee 
obtains fewer than four such Reference Treasury Dealer Quotations, the 
average of all such Quotations "Reference Treasury Dealer Quotations" means, 
with respect to each Reference Treasury Dealer and any redemption date, the 
average, as determined by the Company, 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 Company by such Reference Treasury 
Dealer at 5:00 p.m. on the third business day preceding such redemption date.

          "Reference Treasury Dealer" means (i) each of Salomon Smith Barney 
Inc. ("Salomon") and any other primary U.S. Government securities dealer in 
New York City (a "Primary Treasury Dealer") designated by, and not affiliated 
with, Salomon, PROVIDED, HOWEVER, that if Salomon or any of its designees 
shall cease to be a Primary Treasury Dealer, the Company shall substitute 
therefor another Primary Treasury Dealer, and (ii) any other Primary Treasury 
Dealer or Dealers selected by the Company.

          SECTION 1.04.       In the event that the Company shall desire to 
exercise its right to redeem and pay all or any part of the bonds of 
Collateral Series A pursuant to Section 1.03, it shall, except as modified 
herein, comply with the terms and conditions of Article XI of the Indenture 
with regard to the redemption of bonds of any series secured thereby, and 
such redemption shall be made under and subject to the terms and provisions 
of said Article XI and in the manner and with the effect stated therein; 
provided, however, (a) the Company shall specify, in accordance with the 
provisions of this Supplemental Indenture, those bonds of Collateral Series A 
which are to be redeemed if only a part thereof are to be redeemed, and 
payments in redemption of bonds of Collateral Series A shall be made directly 
by the Company to the registered owners of the bonds entitled thereto; and 
(b) the provisions of Section 11.03(b) of the 1941 Mortgage shall not be 
applicable to any such redemption.  The Company shall not exercise any option 
to redeem on any date all or any part of the bonds of Collateral Series A 
unless it shall give a valid direction under the Senior Indenture for the 
redemption on such date of an equal amount of Related Securities.  Notice of 
each such redemption shall be 

                                       10


hand delivered or mailed, by certified mail, with return receipt requested, 
at least forty-five (45) days prior to the redemption date, to the registered 
owner of the bonds which are to be redeemed at its address appearing on the 
Company's books for registration and registration of transfer.  Such delivery 
or mailing (but not the receipt thereof or the return of the receipt so 
requested) shall be a condition to the redemption of the bonds.  All bonds so 
redeemed shall forthwith be delivered to the Trustee and cancelled, but only 
when the principal, premium, if any, and accrued interest thereon is paid in 
full.  The Trustee, when required to select bonds of Collateral Series A for 
redemption, shall promptly notify the Company, and the Company, when 
selecting bonds of Collateral Series A for redemption, shall promptly notify 
the Trustee, in writing of the distinctive numbers of the bonds selected for 
redemption in whole or in part.  For the purpose only of complying with the 
Indenture (particularly Section 11.02 thereof) in connection with the 
redemption of bonds of Collateral Series A, for each $1,000 principal amount 
of bonds authenticated and delivered hereunder there shall be assigned a 
number in such manner and at such time as the Trustee or the Company shall 
deem appropriate.

          SECTION 1.05.       The Company shall call for redemption all of 
the bonds of the Collateral Series A then outstanding, and shall on the 
redemption date therefor redeem the same at a price equal to 100% of the 
principal amount thereof, together with accrued interest to the redemption 
date, in the event that an event of default has occurred and is continuing 
under Section 6.01 of the Senior Indenture, and the Senior Trustee has 
declared the principal of all Related Securities then outstanding immediately 
due and payable (or such principal has become ipso facto immediately due and 
payable) pursuant to Section 6.02 of the Senior Indenture.  The redemption 
date shall be the accelerated maturity date of the Related Securities; 
provided, however, that such requirement of redemption shall be deemed to be 
waived if prior to the date fixed for such redemption of the bonds of 
Collateral Series A, the acceleration of the Related Securities is waived or 
annulled.  Any provision of Article XI of the Indenture notwithstanding, no 
prior notice of such redemption of the bonds of Collateral Series A to the 
Trustee or the Senior Trustee shall be required.

          SECTION 1.06.       Subject to the provisions of Section 1.04, 
Bonds of Collateral Series A may be redeemed in part, but the portion of any 
such bond so redeemed in part shall be One Thousand Dollars ($1,000) or an 
integral multiple thereof.  In case any bond shall be redeemed in part only, 
payment of the redemption price of such portion of the bond of Collateral 
Series A shall be made by the Company (or Trustee, as the case may be) to the 
registered owner thereof, at its address appearing on the Company's books for 
registration and registration of transfer of bonds of Collateral Series A 
without presentation or surrender thereof, provided there is on file with the 
Company and Trustee (and not theretofore rescinded by written notice from 
such registered owner to the Company and Trustee) a written commitment from 
such registered owner to the effect that (1) payments will be so made, and 
(2) such registered owner will make notations on such bond or a paper 
attached thereto of the portion thereof so redeemed.  Prior to any transfer 
by the registered owner of any bond of Collateral Series A, the same shall be 
surrendered to the Company or Trustee for appropriate notation thereon of, or 
in exchange for a new bond or bonds for, the unredeemed balance of the 
principal amount thereof.  The Trustee shall not be under any duty to 
determine that any of the notations mentioned herein have been made or be 
liable in any manner with respect thereto.

                                      11


          SECTION 1.07.       The Company shall not be obligated to make any 
transfer of bonds of Collateral Series A for a period of fifteen (15) 
calendar days next preceding any interest payment date, or next preceding any 
selection by lot of bonds to be redeemed.  The Company shall not be obligated 
to make transfers of any bonds called or being called for redemption.

          SECTION 1.08.       No charge shall be made to any registered owner 
of any bond of Collateral Series A for any transfer of bonds of said series 
except for any tax or other governmental charge required to be paid in 
connection therewith.

          SECTION 1.09.       The signatures of the President or a Vice 
President and of the Secretary or an Assistant Secretary upon the bonds of 
Collateral Series A may be facsimile signatures imprinted or otherwise 
reproduced on such bonds.  Any such facsimile signature shall have the same 
effect and shall be subject to the same provisions set forth in Section 2.13 
of the 1941 Mortgage as to signatures upon bonds generally.

          SECTION 1.10.       In the event that an interest payment or 
maturity date or a date fixed for redemption of any bond of Collateral Series 
A shall be a Saturday, Sunday or a legal holiday or a day on which banking 
institutions in the city of location of the registered address of the owner 
are authorized by law to close, then payment of interest or principal (and 
premium, if any) need not be made on such date, but may be made on the next 
succeeding business day not a Saturday, Sunday or a legal holiday or a day 
upon which banking institutions in the city of location of the registered 
address of the owner are authorized by law to close, with the same force and 
effect as if made on the date of maturity, interest date, or the date fixed 
for redemption, and no interest shall accrue for the period after such date.

          SECTION 1.11.       Bonds of Collateral Series A which have been 
redeemed or have been paid at maturity shall not be reissued as bonds of said 
series, but may be made the basis for the issuance of additional bonds of any 
series hereafter created, or credits may be taken or cash withdrawn on the 
basis thereof under any applicable provisions of the 1941 Mortgage or any 
future supplemental indenture.


                                  ARTICLE II.

                             CONFIRMATION OF LIEN

          SECTION 2.01.       The Company, in order to record the description 
of, and confirm unto the Trustee, certain property acquired after the 
execution and delivery of the 1941 Mortgage and now subject to the lien 
thereof by virtue of the provisions of the 1941 Mortgage conveying to the 
Trustee property acquired after its execution and delivery, by these presents 
does grant, bargain, sell, warrant, release, convey, assign, transfer, 
mortgage, pledge, set over and confirm unto Firstar Bank Milwaukee, National 
Association, as Trustee, and to its respective successors in said trust 
forever, subject to the rights reserved by the Company in and by other 
provisions of the Indenture and this Supplemental Indenture, all of the 
property described and mentioned or enumerated or referred to in a schedule 
hereto 

                                       12


annexed and marked Schedule A, reference to said schedule for a description 
and enumeration of the property therein described and enumerated being hereby 
made with the same force and effect as if the same were incorporated herein 
at length;

          Together with all and singular the tenements, hereditaments and 
appurtenances belonging or in any wise appertaining to the aforesaid property 
or any part thereof with the reversion and reversions, remainder and 
remainders, tolls, rents and revenues, issues, income, product and profits 
thereof, and all the estate, right, title and interest and claim whatsoever, 
at law as well as in equity, which the Company now has or may hereafter 
acquire in and to the aforesaid property and every part and parcel thereof;

          To have and to hold all said properties, mortgaged, pledged or 
conveyed by the Company as aforesaid, or intended so to be, unto the Trustee 
and its successors and assigns forever, subject, however, to permissible 
encumbrances as defined in the 1941 Mortgage; but in trust, nevertheless, for 
the same purposes and upon the same conditions as are fully set forth in the 
Indenture, which is hereby referred to.
                                       
                                 ARTICLE III.

                     PARTICULAR COVENANTS OF THE COMPANY

          In addition to the covenants contained in the Indenture, the 
Company hereby covenants as follows:

          SECTION 3.01.       That it is duly authorized under the laws of 
the State of Wisconsin and under all other applicable provisions of law to 
create and issue the bonds of Collateral Series A, and to execute and deliver 
this Supplemental Indenture, and that all corporate action on its part for 
the creation and issue of said bonds and the execution of this Supplemental 
Indenture has been duly and effectually taken, and that said bonds when 
issued and delivered to the owners thereof are and will be valid and 
enforceable obligations of the Company, and that the Indenture is and always 
will be a valid mortgage and deed of trust to secure the payment of said 
bonds.

          SECTION 3.02.       That it is lawfully possessed of all the 
property mortgaged and pledged by the Indenture; that it will maintain and 
preserve the lien of the Indenture on the property mortgaged and pledged 
thereby in accordance with the terms thereof and hereof so long as any of the 
bonds issued thereunder are outstanding; and that it has good right and 
lawful authority to mortgage and pledge the property mortgaged and pledged 
thereby as provided in and by the Indenture; and that the same is free and 
clear of all liens and encumbrances, except permissible encumbrances as 
defined in the Indenture.

          SECTION 3.03.       That the Company will duly and punctually pay 
to the registered owner of bonds of Collateral Series A issued under and 
secured by the Indenture and this Supplemental Indenture the principal and 
interest of said bonds at the dates and place and in the manner mentioned in 
such bonds.

                                      13


          SECTION 3.04.       That the Trustee shall not incur any liability 
by reason of any default, failure or delay on the part of the Company to 
observe or perform its covenants contained in this Article III.

                                   ARTICLE IV.

                                  MISCELLANEOUS

          SECTION 4.01.       The recitals of fact herein and in the bonds 
hereby created contained (except the Trustee's Certificate) shall be taken as 
statements of the Company and shall not be construed as made or warranted by 
the Trustee.  The Trustee makes no representations as to the validity of this 
Supplemental Indenture or of the bonds issued under the Indenture by virtue 
hereof.  Except as herein otherwise provided, no duties, responsibilities or 
liabilities are assumed, or shall be construed to be assumed, by the Trustee 
by reason of this Supplemental Indenture other than as set forth in the 
Indenture; and this Supplemental Indenture is executed and accepted on behalf 
of the Trustee, subject to all the terms and conditions set forth in the 
Indenture, as fully to all intents as if the same were herein set forth at 
length.

          SECTION 4.02.       This Supplemental Indenture shall be construed 
in connection with and as a part of the Indenture.

          SECTION 4.03.       (a) Whenever in this Supplemental Indenture 
either of the parties hereto is named or referred to, such reference shall be 
deemed to include the successors or assigns of such party, and all the 
covenants and agreements in this Supplemental Indenture contained by or on 
behalf of the Company or by or on behalf of the Trustee shall bind and inure 
to the benefit of the respective successors and assigns of such parties, 
whether so expressed or not.

          (b)  The table of contents and the descriptive headings of the 
several Articles of this Supplemental Indenture were formulated, used and 
inserted in this Supplemental Indenture for convenience only and shall not be 
deemed to affect the meaning or construction of any of the provisions hereof.

          SECTION 4.04.       (a) If any provision of this Supplemental 
Indenture limits, qualifies, or conflicts with another provision of this 
Supplemental Indenture or of the Indenture required or deemed to be included 
in indentures qualified under the Trust Indenture Act of 1939 (as enacted 
prior to the date of this Supplemental Indenture) by any of Sections 310 to 
317, inclusive, of the said Act, such required provisions shall control.

          (b)  In case any one or more of the provisions contained in this 
Supplemental Indenture or in the bonds, issued hereunder and under the 
Indenture should be invalid, illegal, or unenforceable in any respect, the 
validity, legality and enforceability of the remaining provisions contained 
herein and therein shall not in any way be affected, impaired, prejudiced or 
disturbed thereby.

                                      14


          SECTION 4.05.       This Supplemental Indenture may be executed in 
several counterparts, and all said counterparts executed and delivered, each 
as an original, shall constitute but one and the same instrument.

          SECTION 4.06.       This Supplemental Indenture shall be effective 
and binding from and after the time of actual execution and delivery thereof, 
notwithstanding the fact that such execution and delivery may occur prior or 
subsequent to December 1, 1998.

          SECTION 4.07.       The debtor and its mailing address is WISCONSIN 
PUBLIC SERVICE CORPORATION, 700 North Adams Street, P.O. Box 19001, Green 
Bay, Wisconsin 54307.  The secured party and its address, from which 
information concerning the security interest hereunder may be obtained, is 
FIRSTAR BANK MILWAUKEE, N.A., NATIONAL ASSOCIATION, Corporate Trust 
Department, 1555 North RiverCenter Drive, Suite 301, Milwaukee, Wisconsin 
53212.

                                      15



          IN WITNESS WHEREOF, the party of the first part has caused its 
corporate name and seal to be hereunto affixed and this Supplemental 
Indenture to be signed by its Chairman, President or Vice President, and 
attested by its Secretary or an Assistant Secretary, for and in its behalf, 
and the party of the second part has caused its corporate name and seal to be 
hereunto affixed, and this Supplemental Indenture to be signed by its 
President, a Vice President or an Assistant Vice President, and attested by 
its Secretary or an Assistant Secretary, for and in its behalf, all done as 
of the first day of December, 1998.

                              WISCONSIN PUBLIC SERVICE CORPORATION,


                              By:  /s/ Daniel P. Bittner
                                  --------------------------------
                                   Daniel P. Bittner,
                                   Senior Vice President-Finance
(SEAL)

Attest:

/s/ Francis J. Kicsar
- -------------------------------------
Francis J. Kicsar
Secretary

Executed by Wisconsin Public Service
  Corporation, in presence of:

/s/ Diane L. Behling
- -------------------------------------
Diane L. Behling

/s/ Patti L. Herrmann
- -------------------------------------
Patti L. Herrmann

                                      16


                              FIRSTAR BANK MILWAUKEE, N.A.,
                                  NATIONAL ASSOCIATION
                                   As Trustee,


                              By:  /s/ Amy E. Nolde
                                  -----------------------------------
                                   Amy E. Nolde
                                   Assistant-Vice President
(SEAL)

Attest:


/s/ Yvonne Siira
- -------------------------------------
Yvonne Siira
Assistant Secretary

Executed by Firstar Bank Milwaukee, N.A., National Association
in presence of:

/s/ Lori E. Sandvik
- -------------------------------------
Lori E. Sandvik, Assistant Secretary

/s/ Peter M. Brennan
- -------------------------------------
Peter M. Brennan, Assistant Secretary

                                       17


STATE OF WISCONSIN       }
                         }  ss.
BROWN COUNTY             }

          Personally came before me this 15th day of December, A.D. 1998, 
Daniel P. Bittner, to me known to be the Senior Vice President-Finance, and 
Francis J. Kicsar, to me known to be the Secretary of the above-named 
WISCONSIN PUBLIC SERVICE CORPORATION, the corporation described in and which 
executed the foregoing instrument, and to me known to be the persons who as 
such officers executed the foregoing instrument in the name and behalf of 
said corporation, and acknowledged the same, and acknowledged that the seal 
affixed to said instrument is the corporate seal of said corporation, and 
that they signed, sealed and delivered said instrument in the name and behalf 
of said corporation by authority of its Board of Directors and said Daniel P. 
Bittner and Francis J. Kicsar then and there acknowledged said instrument to 
be the free act and deed of said corporation by each of them voluntarily 
executed.

          Given under my hand and notarial seal this 15th day of December, 
A.D. 1998.

                              /s/ Barth J. Wolf
                              -----------------------------------------
                              Barth J. Wolf
                              Notary Public, Brown County, Wisconsin
                              My commission is permanent.

(NOTARIAL SEAL)

                                       18



STATE OF WISCONSIN       }
                         }  ss.
MILWAUKEE COUNTY         }

          Personally came before me this 15TH day of December, A.D. 1998, AMY 
E. NOLDE, to me known to be a Vice President and YVONNE SIIRA, to me known to 
be an Assistant Secretary of the above-named FIRSTAR BANK MILWAUKEE, N.A., 
NATIONAL ASSOCIATION, the corporation described in and which executed the 
foregoing instrument, and to me known to be the persons who as such officers 
executed the foregoing instrument in the name and behalf of said corporation, 
and acknowledged the same, and acknowledged that the seal affixed to said 
instrument is the corporate seal of said corporation, and that they signed, 
sealed and delivered said instrument in the name and behalf of said 
corporation by authority of its Board of Directors and said AMY E. NOLDE and 
YVONNE SIIRA then and there acknowledged said instrument to be the free act 
and deed of said corporation by each of them voluntarily executed.

          Given under my hand and notarial seal this 15TH day of December, 
A.D. 1998.

                              /s/ F. J. Gingrasso
                              --------------------------------------
                              F. J. Gingrasso
                              Notary Public, Milwaukee County, Wisconsin
                              My commission is permanent

(NOTARIAL SEAL)




This instrument was drafted by Attorney Michael S. Nolan of the law firm of 
Foley & Lardner, Milwaukee, Wisconsin.

                                       19