EXHIBIT 4

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                                  ALLETE, Inc.
                    (formerly Minnesota Power & Light Company
                       and formerly Minnesota Power, Inc.)


                                       TO

                              THE BANK OF NEW YORK
                         (formerly Irving Trust Company)


                                       AND

                               DOUGLAS J. MACINNES
                  (successor to Richard H. West, J. A. Austin,
          E. J. McCabe, D. W. May, J. A. Vaughan and W. T. Cunningham)


                                As Trustees under ALLETE, Inc.'s
                                Mortgage and Deed of Trust dated as of
                                September 1, 1945

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


                      Twenty-fourth Supplemental Indenture

                        Providing among other things for

              First Mortgage Bonds, 5.28% Series due August 1, 2020

                               (Thirtieth Series)



                            DATED AS OF MARCH 1, 2005


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                      TWENTY-FOURTH SUPPLEMENTAL INDENTURE

         THIS INDENTURE,  dated as of March 1, 2005, by and between ALLETE, INC.
(formerly Minnesota Power & Light Company and formerly Minnesota Power, Inc.), a
corporation  of the State of  Minnesota,  whose post  office  address is 30 West
Superior  Street,  Duluth,  Minnesota 55802  (hereinafter  sometimes  called the
"Company"),  and  THE  BANK OF NEW  YORK  (formerly  Irving  Trust  Company),  a
corporation  of the State of New York,  whose post office address is 101 Barclay
Street,  New York, New York 10286  (hereinafter  sometimes called the "Corporate
Trustee"),  and DOUGLAS J. MACINNES (successor to Richard H. West, J. A. Austin,
E. J. McCabe, D. W. May, J. A. Vaughan and W. T. Cunningham),  whose post office
address is 1784 W. McGalliard Avenue,  Hamilton,  New Jersey 08610 (said Douglas
J.  MacInnes  being  hereinafter  sometimes  called  the  "Co-Trustee"  and  the
Corporate Trustee and the Co-Trustee being hereinafter together sometimes called
the "Trustees"),  as Trustees under the Mortgage and Deed of Trust,  dated as of
September 1, 1945,  between the Company and Irving Trust  Company and Richard H.
West, as Trustees,  securing  bonds issued and to be issued as provided  therein
(hereinafter  sometimes called the  "Mortgage"),  reference to which mortgage is
hereby made, this indenture  (hereinafter  sometimes  called the  "Twenty-fourth
Supplemental Indenture") being supplemental thereto:

         WHEREAS,  the  Mortgage  was filed and  recorded  in  various  official
records in the State of Minnesota; and

         WHEREAS, an instrument,  dated as of October 16, 1957, was executed and
delivered under which J. A. Austin succeeded Richard H. West as Co-Trustee under
the Mortgage,  and such  instrument  was filed and recorded in various  official
records in the State of Minnesota; and

         WHEREAS,  an  instrument,  dated as of April 4, 1967,  was executed and
delivered  under which E. J. McCabe in turn succeeded J. A. Austin as Co-Trustee
under the  Mortgage,  and such  instrument  was filed and  recorded  in  various
official records in the State of Minnesota; and

         WHEREAS, under the Sixth Supplemental Indenture,  dated as of August 1,
1975, to which reference is hereinafter  made, D. W. May in turn succeeded E. J.
McCabe as Co-Trustee under the Mortgage; and

         WHEREAS,  an  instrument,  dated as of June 25, 1984,  was executed and
delivered  under which J. A. Vaughan in turn  succeeded D. W. May as  Co-Trustee
under the  Mortgage,  and such  instrument  was filed and  recorded  in  various
official records in the State of Minnesota; and

         WHEREAS,  an  instrument,  dated as of July 27, 1988,  was executed and
delivered  under  which W. T.  Cunningham  in turn  succeeded  J. A.  Vaughan as
Co-Trustee  under the Mortgage,  and such  instrument  was filed and recorded in
various official records in the State of Minnesota; and

         WHEREAS,  on May 12,  1998,  the Company  filed  Amended  and  Restated
Articles of Incorporation  with the Secretary of State of the State of Minnesota
changing its name from Minnesota Power & Light Company to Minnesota Power,  Inc.
effective May 27, 1998; and



                                       2

         WHEREAS,  an  instrument,  dated as of April 15, 1999, was executed and
delivered  under which Douglas J. MacInnes in turn succeeded W. T. Cunningham as
Co-Trustee  under the Mortgage,  and such  instrument  was filed and recorded in
various official records in the State of Minnesota; and

         WHEREAS,  on May 8,  2001,  the  Company  filed  Amended  and  Restated
Articles of Incorporation  with the Secretary of State of the State of Minnesota
changing its name from Minnesota Power, Inc. to ALLETE, Inc.; and

         WHEREAS,  by the Mortgage the Company  covenanted,  among other things,
that it would execute and deliver such supplemental  indenture or indentures and
such  further  instruments  and do such  further  acts as might be  necessary or
proper to carry out more  effectually  the  purposes of the Mortgage and to make
subject  to the  lien of the  Mortgage  any  property  thereafter  acquired  and
intended to be subject to the lien thereof; and

         WHEREAS,  for said  purposes,  among others,  the Company  executed and
delivered the following indentures supplemental to the Mortgage:

         DESIGNATION                                         DATED AS OF
         -----------                                         -----------
First Supplemental Indenture.............................    March 1, 1949
Second Supplemental Indenture............................    July 1, 1951
Third Supplemental Indenture.............................    March 1, 1957
Fourth Supplemental Indenture............................    January 1, 1968
Fifth Supplemental Indenture.............................    April 1, 1971
Sixth Supplemental Indenture.............................    August 1, 1975
Seventh Supplemental Indenture...........................    September 1, 1976
Eighth Supplemental Indenture............................    September 1, 1977
Ninth Supplemental Indenture.............................    April 1, 1978
Tenth Supplemental Indenture.............................    August 1, 1978
Eleventh Supplemental Indenture..........................    December 1, 1982
Twelfth Supplemental Indenture...........................    April 1, 1987
Thirteenth Supplemental Indenture........................    March 1, 1992
Fourteenth Supplemental Indenture........................    June 1, 1992
Fifteenth Supplemental Indenture.........................    July 1, 1992
Sixteenth Supplemental Indenture.........................    July 1, 1992
Seventeenth Supplemental Indenture.......................    February 1, 1993
Eighteenth Supplemental Indenture........................    July 1, 1993
Nineteenth Supplemental Indenture........................    February 1, 1997
Twentieth Supplemental Indenture.........................    November 1, 1997
Twenty-first Supplemental Indenture......................    October 1, 2000
Twenty-second Supplemental Indenture.....................    July 1, 2003
Twenty-third Supplemental Indenture......................    August 1, 2004


which  supplemental  indentures  were filed and  recorded  in  various  official
records in the State of Minnesota; and



                                       3

         WHEREAS,  the Company has  heretofore  issued,  in accordance  with the
provisions of the Mortgage, as heretofore supplemented,  the following series of
First Mortgage Bonds:

                                                     PRINCIPAL      PRINCIPAL
                                                      AMOUNT         AMOUNT
SERIES                                                ISSUED       OUTSTANDING
- ------                                               ---------     -----------

3-1/8% Series due 1975...........................   $26,000,000       None
3-1/8% Series due 1979...........................     4,000,000       None
3-5/8% Series due 1981...........................    10,000,000       None
4-3/4% Series due 1987...........................    12,000,000       None
6-1/2% Series due 1998...........................    18,000,000       None
8-1/8% Series due 2001...........................    23,000,000       None
10-1/2% Series due 2005..........................    35,000,000       None
8.70% Series due 2006............................    35,000,000       None
8.35% Series due 2007............................    50,000,000       None
9-1/4% Series due 2008...........................    50,000,000       None
Pollution Control Series A.......................   111,000,000       None
Industrial Development Series A..................     2,500,000       None
Industrial Development Series B..................     1,800,000       None
Industrial Development Series C..................     1,150,000       None
Pollution Control Series B.......................    13,500,000       None
Pollution Control Series C.......................     2,000,000       None
Pollution Control Series D.......................     3,600,000       None
7-3/4% Series due 1994...........................    55,000,000       None
7-3/8% Series due March 1, 1997..................    60,000,000       None
7-3/4% Series due June 1, 2007...................    55,000,000       None
7-1/2% Series due August 1, 2007.................    35,000,000   $35,000,000
Pollution Control Series E.......................   111,000,000       None
7% Series due March 1, 2008......................    50,000,000    50,000,000
6-1/4% Series due July 1, 2003...................    25,000,000       None
7% Series due February 15, 2007..................    60,000,000    60,000,000
6.68% Series due November 15, 2007...............    20,000,000    20,000,000
Floating Rate Series due October 20, 2003........   250,000,000       None
Collateral Series A..............................   255,000,000       None
Pollution Control Series F.......................   111,000,000    111,000,000


which bonds are also  hereinafter  sometimes  called bonds of the First  through
Twenty-ninth Series, respectively; and

         WHEREAS,  Section  8 of the  Mortgage  provides  that  the form of each
series of bonds (other than the First Series)  issued  thereunder and of coupons
to be attached to coupon bonds of such series shall be established by Resolution
of the Board of Directors  of the Company and that the form of such  series,  as
established by said Board of Directors,  shall specify the descriptive  title of
the bonds and various other terms thereof,  and may also contain such provisions
not inconsistent with the



                                       4

provisions  of the  Mortgage as the Board of Directors  may, in its  discretion,
cause to be inserted therein expressing or referring to the terms and conditions
upon which such bonds are to be issued and/or secured under the Mortgage; and

         WHEREAS, Section 120 of the Mortgage provides, among other things, that
any power,  privilege or right expressly or impliedly  reserved to or in any way
conferred upon the Company by any provision of the Mortgage, whether such power,
privilege  or right is in any way  restricted  or is  unrestricted,  may (to the
extent  permitted  by law) be in  whole  or in part  waived  or  surrendered  or
subjected  to any  restriction  if at the  time  unrestricted  or to  additional
restriction  if already  restricted,  and the Company may enter into any further
covenants, limitations or restrictions for the benefit of any one or more series
of bonds  issued  thereunder,  or the Company may cure any  ambiguity  contained
therein,  or in any  supplemental  indenture,  or may  establish  the  terms and
provisions  of any  series  of  bonds  (other  than  said  First  Series)  by an
instrument in writing executed and acknowledged by the Company in such manner as
would be necessary  to entitle a  conveyance  of real estate to record in all of
the states in which any property at the time subject to the lien of the Mortgage
shall be situated; and

         WHEREAS,  the  Company  now desires to create a new series of bonds and
(pursuant  to the  provisions  of  Section  120 of the  Mortgage)  to add to its
covenants and agreements contained in the Mortgage, as heretofore  supplemented,
certain  other  covenants  and  agreements to be observed by it and to alter and
amend  in  certain  respects  the  covenants  and  provisions  contained  in the
Mortgage, as heretofore supplemented; and

         WHEREAS,   the   execution   and   delivery  by  the  Company  of  this
Twenty-fourth  Supplemental  Indenture,  and  the  terms  of  the  bonds  of the
Thirtieth  Series,  hereinafter  referred to, have been duly  authorized  by the
Board of Directors of the Company by  appropriate  resolutions  of said Board of
Directors;

         NOW, THEREFORE, THIS INDENTURE WITNESSETH:

         That the Company, in consideration of the premises and of One Dollar to
it duly paid by the  Trustees at or before the  ensealing  and delivery of these
presents, the receipt whereof is hereby acknowledged, and in further evidence of
assurance of the estate,  title and rights of the Trustees and in order  further
to secure the payment of both the principal of and interest and premium, if any,
on the  bonds  from  time to time  issued  under  the  Mortgage,  as  heretofore
supplemented, according to their tenor and effect and the performance of all the
provisions of the Mortgage (including any instruments  supplemental  thereto and
any  modification  made as in the Mortgage  provided) and of said bonds,  hereby
grants,  bargains,  sells, releases,  conveys,  assigns,  transfers,  mortgages,
pledges,  sets over and confirms (subject,  however,  to Excepted  Encumbrances)
unto THE BANK OF NEW YORK  and  DOUGLAS  J.  MACINNES,  as  Trustees  under  the
Mortgage,  and to their  successor  or  successors  in said  trust,  and to said
Trustees and their successors and assigns forever, all property,  real, personal
and mixed,  of the kind or nature  specifically  mentioned in the  Mortgage,  as
heretofore supplemented,  or of any other kind or nature acquired by the Company
after the date of the  execution  and delivery of the  Mortgage,  as  heretofore
supplemented (except any herein or in the Mortgage, as heretofore  supplemented,
expressly  excepted),  now owned or, subject to the provisions of subsection (I)
of



                                       5

Section 87 of the  Mortgage,  hereafter  acquired by the  Company (by  purchase,
consolidation, merger, donation, construction, erection or in any other way) and
wheresoever situated, including (without in anywise limiting or impairing by the
enumeration  of the same the scope and intent of the foregoing or of any general
description contained in this Twenty-fourth  Supplemental  Indenture) all lands,
power  sites,   flowage   rights,   water   rights,   water   locations,   water
appropriations,  ditches, flumes, reservoirs, reservoir sites, canals, raceways,
dams,  dam sites,  aqueducts,  and all other rights or means for  appropriating,
conveying,  storing and supplying water; all rights of way and roads; all plants
for the generation of electricity by steam,  water and/or other power; all power
houses,  gas plants,  street  lighting  systems,  standards and other  equipment
incidental thereto,  telephone,  radio and television systems,  air-conditioning
systems and equipment incidental thereto, water works, water systems, steam heat
and hot water plants,  substations,  lines, service and supply systems, bridges,
culverts, tracks, ice or refrigeration plants and equipment,  offices, buildings
and other structures and the equipment thereof; all machinery, engines, boilers,
dynamos,  electric, gas and other machines,  regulators,  meters,  transformers,
generators, motors, electrical, gas and mechanical appliances, conduits, cables,
water,  steam heat,  gas or other  pipes,  gas mains and pipes,  service  pipes,
fittings,  valves and connections,  pole and transmission lines, wires,  cables,
tools,  implements,  apparatus,  furniture and chattels; all municipal and other
franchises, consents or permits; all lines for the transmission and distribution
of electric current,  gas, steam heat or water for any purpose including towers,
poles,  wires,  cables,  pipes,  conduits,  ducts and all  apparatus  for use in
connection therewith; all real estate, lands, easements,  servitudes,  licenses,
permits, franchises,  privileges,  rights of way and other rights in or relating
to real  estate or the  occupancy  of the same and  (except  as herein or in the
Mortgage, as heretofore  supplemented,  expressly excepted) all the right, title
and  interest of the Company in and to all other  property of any kind or nature
appertaining  to and/or used and/or  occupied  and/or enjoyed in connection with
any  property  hereinbefore  or in the  Mortgage,  as  heretofore  supplemented,
described.

         TOGETHER   WITH  all  and   singular  the   tenements,   hereditaments,
prescriptions, servitudes and appurtenances belonging or in anywise appertaining
to  the  aforesaid  property  or  any  part  thereof,  with  the  reversion  and
reversions,  remainder and  remainders and (subject to the provisions of Section
57 of the  Mortgage)  the tolls,  rents,  revenues,  issues,  earnings,  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 franchises and every part
and parcel thereof.

         IT IS HEREBY AGREED by the Company that,  subject to the  provisions of
subsection  (I) of Section 87 of the  Mortgage,  all the property,  rights,  and
franchises  acquired  by  the  Company  (by  purchase,  consolidation,   merger,
donation,  construction,  erection  or in any other way) after the date  hereof,
except any herein or in the  Mortgage,  as  heretofore  supplemented,  expressly
excepted,  shall be and are as fully  granted  and  conveyed  hereby  and by the
Mortgage  and as  fully  embraced  within  the lien  hereof  and the lien of the
Mortgage  as if such  property,  rights  and  franchises  were now  owned by the
Company and were  specifically  described herein or in the Mortgage and conveyed
hereby or thereby.

         PROVIDED  that the  following are not and are not intended to be now or
hereafter granted, bargained, sold, released, conveyed,  assigned,  transferred,
mortgaged, hypothecated,  affected,



                                       6

pledged,  set over or confirmed hereunder and are hereby expressly excepted from
the lien and operation of this Twenty-fourth Supplemental Indenture and from the
lien and operation of the Mortgage,  namely:  (1) cash, shares of stock,  bonds,
notes and other  obligations  and other  securities  not hereafter  specifically
pledged, paid, deposited,  delivered or held under the Mortgage or covenanted so
to be; (2) merchandise, equipment, apparatus, materials or supplies held for the
purpose of sale or other disposition in the usual course of business;  fuel, oil
and similar  materials  and supplies  consumable  in the operation of any of the
properties of the Company; all aircraft,  rolling stock, trolley coaches, buses,
motor  coaches,  automobiles  and other vehicles and materials and supplies held
for the purpose of repairing  or  replacing  (in whole or part) any of the same;
all  timber,  minerals,  mineral  rights and  royalties;  (3)  bills,  notes and
accounts receivable, judgments, demands and choses in action, and all contracts,
leases and operating  agreements not specifically  pledged under the Mortgage or
covenanted so to be; the Company's  contractual  rights or other  interest in or
with respect to tires not owned by the Company;  (4) the last day of the term of
any lease or leasehold  which may  hereafter  become  subject to the lien of the
Mortgage;  (5) electric energy, gas, steam, ice, and other materials or products
generated,  manufactured,  produced  or  purchased  by  the  Company  for  sale,
distribution  or  use in the  ordinary  course  of its  business;  and  (6)  the
Company's franchise to be a corporation;  provided,  however,  that the property
and rights expressly  excepted from the lien and operation of this Twenty-fourth
Supplemental  Indenture  and from the lien and  operation of the Mortgage in the
above  subdivisions  (2) and (3) shall (to the extent permitted by law) cease to
be so  excepted  in the  event  and as of the date  that  either  or both of the
Trustees or a receiver or trustee  shall enter upon and take  possession  of the
Mortgaged  and Pledged  Property in the manner  provided in Article  XIII of the
Mortgage  by reason of the  occurrence  of a Default  as  defined  in Section 65
thereof.

         TO HAVE AND TO HOLD all such  properties,  real,  personal  and  mixed,
granted, bargained, sold, released, conveyed, assigned, transferred,  mortgaged,
pledged,  set over or confirmed by the Company as  aforesaid,  or intended so to
be, unto the Trustees and their successors and assigns forever.

         IN TRUST  NEVERTHELESS,  for the same purposes and upon the same terms,
trusts and conditions and subject to and with the same provisos and covenants as
are set forth in the Mortgage, as supplemented,  this Twenty-fourth Supplemental
Indenture being supplemental thereto.

         AND IT IS  HEREBY  COVENANTED  by  the  Company  that  all  the  terms,
conditions,  provisos,  covenants and provisions  contained in the Mortgage,  as
heretofore  supplemented,  shall affect and apply to the  property  hereinbefore
described and conveyed and to the estate, rights,  obligations and duties of the
Company and  Trustees  and the  beneficiaries  of the trust with respect to said
property,  and to the  Trustees  and their  successors  in the trust in the same
manner  and with the  same  effect  as if said  property  had been  owned by the
Company at the time of the execution of the Mortgage,  and had been specifically
and at length  described in and  conveyed to said  Trustees by the Mortgage as a
part of the property therein stated to be conveyed.

         The Company  further  covenants and agrees to and with the Trustees and
their successors in said trust under the Mortgage as follows:


                                       7


                                    ARTICLE I
                            THIRTIETH SERIES OF BONDS


         SECTION 1. There shall be a series of bonds  designated  "5.28%  Series
due August 1, 2020" (herein  sometimes  referred to as the "Thirtieth  Series"),
each of which shall also bear the descriptive  title "First Mortgage Bond",  and
the form  thereof,  which shall be  established  by  Resolution  of the Board of
Directors of the Company,  shall contain suitable provisions with respect to the
matters  hereinafter in this Section  specified.  Bonds of the Thirtieth  Series
shall be dated as in Section 10 of the  Mortgage  provided,  mature on August 1,
2020,  be issued as fully  registered  bonds in  denominations  of One  Thousand
Dollars and, at the option of the  Company,  in any multiple or multiples of One
Thousand  Dollars (the  exercise of such option to be evidenced by the execution
and delivery thereof) and bear interest from August 1, 2005 at the rate of 5.28%
per  annum,  payable  semi-annually  on  February  1 and  August 1 of each year,
commencing  February 1, 2006, the principal of and interest on each said bond to
be payable at the office or agency of the Company in the  Borough of  Manhattan,
The City of New York,  in such coin or currency of the United  States of America
as at the time of payment is legal tender for public and private debts.

         (I) OPTIONAL PREPAYMENT. The Company may, at its option, upon notice as
provided below, prepay at any time all, or from time to time any part of, the
bonds of the Thirtieth Series at 100% of the principal amount so prepaid, and
the Make-Whole Amount determined for the Settlement Date specified by the
Company in such notice with respect to such principal amount. The Company will
give each registered owner of Bonds of the Thirtieth Series written notice (by
first class mail or such other method as may be agreed upon by the Company and
such registered owner) of each optional prepayment under this subsection (I)
mailed or otherwise given not less than 30 days and not more than 60 days prior
to the date fixed for such prepayment, to each such registered owner at his, her
or its last address appearing on the registry books. Each such notice shall
specify the Settlement Date (which shall be a Business Day), the aggregate
principal amount of the bonds of the Thirtieth Series to be prepaid on such
date, the principal amount of each bond held by such registered owner to be
prepaid (determined in accordance with subsection (II) of this section), and the
interest to be paid on the Settlement Date with respect to such principal amount
being prepaid, and shall be accompanied by a certificate signed by a Senior
Financial Officer as to the estimated Make-Whole Amount due in connection with
such prepayment (calculated as if the date of such notice were the date of the
prepayment), setting forth the details of such computation. Two Business Days
prior to such Settlement Date, the Company shall send to each registered owner
of bonds of the Thirtieth Series (by first class mail or by such other method as
may be agreed upon by the Company and such registered owner) a certificate
signed by a Senior Financial Officer specifying the calculation of such
Make-Whole Amount as of the specified Settlement Date. As promptly as
practicable after the giving of the notice and the sending of the certificates
provided in this subsection, the Company shall provide a copy of each to the
Corporate Trustee. The Trustees shall be under no duty to inquire into, may
conclusively presume the correctness of, and shall be fully protected in relying
upon the information set forth in any such notice or certificate. The bonds of
the Thirtieth Series are not otherwise subject to voluntary or optional
prepayment.
         (II)  ALLOCATION  OF PARTIAL  PREPAYMENTS.  In the case of each partial
prepayment of the bonds of the  Thirtieth  Series,  the principal  amount of the
Bonds of the  Thirtieth  Series to be prepaid


                                       8

shall be allocated by the Company among all of the Bonds of the Thirtieth Series
at the  time  outstanding  in  proportion,  as  nearly  as  practicable,  to the
respective  unpaid  principal   amounts  thereof  not  theretofore   called  for
prepayment.

         (III)  MATURITY;  SURRENDER,  ETC.  In  the  case  of  each  notice  of
prepayment of bonds of the Thirtieth  Series  pursuant to this section,  if cash
sufficient  to pay the  principal  amount to be prepaid on the  Settlement  Date
(which shall be a Business Day), together with interest on such principal amount
accrued to such date and the applicable  Make-Whole  Amount, if any, is not paid
as agreed upon by the Company and each  registered  owner of the affected bonds,
or, to the extent that there is no such agreement  entered into with one or more
such owners,  deposited  with the Corporate  Trustee on or before the Settlement
Date, then such notice of prepayment  shall be of no effect.  If such cash is so
paid or deposited,  such principal  amount of the bonds of the Thirtieth  Series
shall be deemed paid for all  purposes  and  interest on such  principal  amount
shall cease to accrue. In case the Company pays any registered owner pursuant to
an agreement with that registered  owner, the Company shall notify the Corporate
Trustee as promptly as  practicable  of such  agreement  and payment,  and shall
furnish the Corporate Trustee with a copy of such agreement; in case the Company
deposits  any  cash  with the  Corporate  Trustee,  the  Company  shall  provide
therewith  a list of the  registered  owners  and the  amount  of such cash each
registered  owner is to receive.  The Trustees shall be under no duty to inquire
into, may conclusively  presume the correctness of, and shall be fully protected
in relying upon the information set forth in any such notice, list or agreement,
and shall not be  chargeable  with  knowledge of any of the contents of any such
agreement.  Any bond prepaid in full shall be  surrendered to the Company or the
Corporate  Trustee for  cancellation  on or before the Settlement  Date or, with
respect to cash  deposited  with the Corporate  Trustee,  before payment of such
cash by the Corporate Trustee;  any bond prepaid in part shall be surrendered to
the Company or the Corporate  Trustee on or before the  Settlement  Date (unless
otherwise agreed between the Company and the registered  owner) or, with respect
to cash  deposited  with  Corporate  Trustee  before payment of such cash by the
Corporate  Trustee,  for a substitute  bond in the  principal  amount  remaining
unpaid.

         (IV) MAKE-WHOLE AMOUNT.

         "Make-Whole  Amount"  means,  with respect to any bond of the Thirtieth
Series,  an amount equal to the excess,  if any, of the Discounted  Value of the
Remaining  Scheduled  Payments with respect to the Called Principal of such bond
of the Thirtieth Series over the amount of such Called Principal,  provided that
the  Make-Whole  Amount may in no event be less than zero.  For the  purposes of
determining  the  Make-Whole  Amount,  the  following  terms have the  following
meanings:

         "Business  Day" means any day other than a Saturday,  a Sunday or a day
on which  commercial  banks in New York City are  required or  authorized  to be
closed.

         "Called  Principal"  means,  with respect to any bond of the  Thirtieth
Series,  the principal of such bond that is to be prepaid pursuant to subsection
(I) of this section.

         "Discounted  Value" means,  with respect to the Called Principal of any
bond of the Thirtieth  Series,  the amount obtained by discounting all Remaining
Scheduled  Payments with respect to such Called  Principal from their respective
scheduled due dates to the Settlement Date with respect to such


                                       9

Called  Principal,  in  accordance  with  accepted  financial  practice and at a
discount factor (applied on the same periodic basis as that on which interest on
the bonds of the Thirtieth  Series is payable) equal to the  Reinvestment  Yield
with respect to such Called Principal.

         "Reinvestment Yield" means, with respect to the Called Principal of any
bond of the Thirtieth Series, 0.5% over the yield to maturity implied by (i) the
yields reported as of 10:00 a.m. (New York City time) on the second Business Day
preceding  the  Settlement  Date with respect to such Called  Principal,  on the
display  designated as "Page PX1" (or such other display as may replace Page PX1
on Bloomberg  Financial Markets  ("Bloomberg") or, if Page PX1 (or its successor
screen on Bloomberg) is  unavailable,  the Telerate  Access Service screen which
corresponds  most  closely  to Page PX1 for the most  recently  issued  actively
traded U.S. Treasury securities having a maturity equal to the Remaining Average
Life of such Called Principal as of such Settlement Date, or (ii) if such yields
are not reported as of such time or the yields  reported as of such time are not
ascertainable  (including  by  way  of  interpolation),  the  Treasury  Constant
Maturity Series Yields  reported,  for the latest day for which such yields have
been so reported as of the second  Business Day  preceding the  Settlement  Date
with respect to such Called Principal,  in Federal Reserve  Statistical  Release
H.15 (519) (or any comparable  successor  publication)  for actively traded U.S.
Treasury  securities  having a constant  maturity equal to the Remaining Average
Life of such Called  Principal as of such  Settlement  Date.  Such implied yield
will  be  determined,  if  necessary,  by  (a)  converting  U.S.  Treasury  bill
quotations  to bond  equivalent  yields in accordance  with  accepted  financial
practice and (b)  interpolating  linearly  between (1) the actively  traded U.S.
Treasury  security with the maturity  closest to and greater than such Remaining
Average  Life  and (2) the  actively  traded  U.S.  Treasury  security  with the
maturity closest to and less than such Remaining  Average Life. The Reinvestment
Yield  shall be  rounded  to the  number of  decimal  places as  appears  in the
interest rate of the applicable bond of the Thirtieth Series.

         "Remaining  Average Life" means,  with respect to any Called Principal,
the number of years  (calculated  to the nearest  one-twelfth  year) obtained by
dividing (i) such Called Principal into (ii) the sum of the products obtained by
multiplying (a) the principal component of each Remaining Scheduled Payment with
respect to such Called  Principal by (b) the number of years  (calculated to the
nearest  one-twelfth  year) that will elapse  between the  Settlement  Date with
respect to such Called  Principal and the  scheduled due date of such  Remaining
Scheduled Payment.

         "Remaining  Scheduled  Payments"  means,  with  respect  to the  Called
Principal  of any Bond of the  Thirtieth  Series,  all  payments  of such Called
Principal and interest  thereon that would be due after the Settlement Date with
respect to such Called  Principal  if no payment of such Called  Principal  were
made prior to its scheduled due date,  provided that if such  Settlement Date is
not a date on which interest  payments are due to be made under the terms of the
Bonds of the Thirtieth Series, then the amount of the next succeeding  scheduled
interest  payment  will be  reduced by the  amount of  interest  accrued to such
Settlement  Date and  required to be paid on such  Settlement  Date  pursuant to
subsection (I) of this section.

         "Settlement  Date" means,  with respect to the Called  Principal of any
Bond of the Thirtieth  Series,  the date on which such Called Principal is to be
prepaid pursuant to subsection (I) of this section.


                                       10

         "Senior Financial Officer" means the chief financial officer, principal
accounting officer, treasurer or comptroller of the Company.

         (V) DIVIDEND COVENANT. If any series of bonds under the Mortgage has
the benefit of the dividend covenant in Section 39(III) of the Mortgage, then,
so long as such series of bonds remains outstanding and such dividend covenant
remains in effect, the bonds of the Thirtieth Series shall have the benefit of
such dividend covenant; provided however that no consent or vote of the holders
of the bonds of the Thirtieth Series shall be required to modify or eliminate
such dividend covenant to the extent, if any, that such dividend covenant may be
modified or eliminated at the request of the Company with the vote or consent of
the holders of the required aggregate principal amount of any series of
outstanding bonds whose consent is required by the Mortgage for such
modification or elimination and the Company has obtained any such required vote
or consent.

         (VI) At the option of the registered  owner, any bonds of the Thirtieth
Series,  upon surrender  thereof for cancellation at the office or agency of the
Company  in the  Borough of  Manhattan,  The City of New York,  together  with a
written instrument of transfer wherever required by the Company duly executed by
the registered owner or by his duly authorized  attorney,  shall (subject to the
provisions of Section 12 of the Mortgage) be  exchangeable  for a like aggregate
principal amount of bonds of the same series of other authorized denominations.

         Bonds of the  Thirtieth  Series shall be  transferable  (subject to the
provisions of Section 12 of the Mortgage) at the office or agency of the Company
in the Borough of  Manhattan,  The City of New York.  The  Company  shall not be
required to make  transfers or exchanges of bonds of the Thirtieth  Series for a
period of ten (10) days next  preceding any  designation of bonds of said series
to be prepaid,  and the  Company  shall not be  required  to make  transfers  or
exchanges  of any  bonds  of said  series  designated  in  whole  or in part for
prepayment.

         Upon any  exchange or transfer of bonds of the  Thirtieth  Series,  the
Company may make a charge  therefor  sufficient  to  reimburse it for any tax or
taxes or other  governmental  charge, as provided in Section 12 of the Mortgage,
but the Company hereby waives any right to make a charge in addition thereto for
any exchange or transfer of bonds of the Thirtieth Series.

         After the delivery of this  Twenty-fourth  Supplemental  Indenture  and
upon  compliance  with the applicable  provisions of the Mortgage and receipt of
consideration  therefor by the Company, there shall be an initial issue of bonds
of the Thirtieth Series for the aggregate principal amount of $35,000,000.


                                   ARTICLE II
                            MISCELLANEOUS PROVISIONS


         SECTION 2.  Section 126 of the  Mortgage,  as  heretofore  amended,  is
hereby further amended by adding the words "and August 1, 2020," after the words
"and July 1, 2022."


                                       11

         SECTION 3. Subject to the amendments provided for in this Twenty-fourth
Supplemental  Indenture,  the  terms  defined  in the  Mortgage,  as  heretofore
supplemented,  shall,  for  all  purposes  of  this  Twenty-fourth  Supplemental
Indenture,   have  the  meanings  specified  in  the  Mortgage,   as  heretofore
supplemented.

         SECTION 4. The holders of bonds of the  Thirtieth  Series  consent that
the  Company  may,  but shall not be  obligated  to,  fix a record  date for the
purpose of determining the holders of bonds of the Thirtieth  Series entitled to
consent to any amendment, supplement or waiver. If a record date is fixed, those
persons who were holders at such record date (or their duly designated proxies),
and only  those  persons,  shall  be  entitled  to  consent  to such  amendment,
supplement or waiver or to revoke any consent  previously given,  whether or not
such  persons  continue to be holders  after such record  date.  No such consent
shall be valid or effective for more than 90 days after such record date.

         SECTION 5. The  Trustees  hereby  accept the  trusts  herein  declared,
provided,  created or supplemented  and agree to perform the same upon the terms
and conditions herein and in the Mortgage set forth and upon the following terms
and conditions:

         The Trustees shall not be  responsible in any manner  whatsoever for or
in respect of the validity or  sufficiency  of this  Twenty-fourth  Supplemental
Indenture or for or in respect of the recitals  contained  herein,  all of which
recitals  are made by the Company  solely.  In general,  each and every term and
condition contained in Article XVII of the Mortgage shall apply to and form part
of this Twenty-fourth  Supplemental  Indenture with the same force and effect as
if the same were herein set forth in full with such  omissions,  variations  and
insertions,  if any,  as may be  appropriate  to make  the same  conform  to the
provisions of this Twenty-fourth Supplemental Indenture.

         SECTION 6. Whenever in this  Twenty-fourth  Supplemental  Indenture any
party hereto is named or referred to, this shall,  subject to the  provisions of
Articles XVI and XVII of the Mortgage, as heretofore supplemented,  be deemed to
include the  successors  or assigns of such  party,  and all the  covenants  and
agreements  in this  Twenty-fourth  Supplemental  Indenture  contained  by or on
behalf of the  Company,  or by or on behalf of the  Trustees  shall,  subject as
aforesaid,  bind and  inure to the  benefit  of the  respective  successors  and
assigns of such party whether so expressed or not.

         SECTION  7.  Nothing  in  this  Twenty-fourth  Supplemental  Indenture,
expressed or implied,  is intended,  or shall be  construed,  to confer upon, or
give to, any person, firm or corporation,  other than the parties hereto and the
holders of the bonds and  coupons  Outstanding  under the  Mortgage,  any right,
remedy, or claim under or by reason of this Twenty-fourth Supplemental Indenture
or any covenant,  condition,  stipulation,  promise or agreement hereof, and all
the  covenants,  conditions,  stipulations,  promises  and  agreements  in  this
Twenty-fourth  Supplemental  Indenture contained by and on behalf of the Company
shall be for the sole and exclusive  benefit of the parties  hereto,  and of the
holders of the bonds and of the coupons Outstanding under the Mortgage.

         SECTION 8. This Twenty-fourth  Supplemental Indenture shall be executed
in several  counterparts,  each of which shall be an  original  and all of which
shall constitute but one and the same instrument.


                                       12

         SECTION 9. The Company,  the mortgagor  named herein,  by its execution
hereof  acknowledges  receipt  of  a  full,  true  and  complete  copy  of  this
Twenty-fourth Supplemental Indenture.


                                       13

IN WITNESS  WHEREOF,  ALLETE,  Inc. has caused its corporate name to be hereunto
affixed,  and this instrument to be signed and sealed by its President or one of
its Vice  Presidents,  and its corporate seal to be attested by its Secretary or
one of its  Assistant  Secretaries  for and in its  behalf,  all in the  City of
Duluth,  Minnesota, and The Bank of New York has caused its corporate name to be
hereunto affixed, and this instrument to be signed and sealed by one of its Vice
Presidents or one of its Assistant Vice  Presidents and its corporate seal to be
attested by one of its Assistant  Treasurers,  one of its Vice Presidents or one
of its Assistant Vice  Presidents,  and Douglas J. MacInnes has hereunto set his
hand and affixed his seal,  all in The City of New York,  as of the day and year
first above written.

                                      ALLETE, INC.


                                      By     /s/ James K. Vizanko
                                         ---------------------------------------
                                             James K. Vizanko
                                             Senior Vice President and Chief
                                                    Financial Officer
Attest:

/s/ Deborah A. Amberg
- ---------------------------------
Deborah A. Amberg
Vice President, General Counsel
         and Secretary


Executed, sealed and delivered by
ALLETE, INC. in the presence of:


/s/ Teresa Patterson
- --------------------------------

/s/ Dawn LaPointe Garbo
- --------------------------------


                                       14


                                      THE BANK OF NEW YORK,
                                            as Trustee


                                      By     /s/ Ming Ryan
                                        ----------------------------------------
                                             Ming Ryan
                                             Vice President


Attest:

/s/ Geovanni Barris
- --------------------------------
Geovanni Barris
Vice President


                                             /s/ Douglas J. MacInnes        L.S.
                                      ------------------------------------------
                                             DOUGLAS J. MACINNES


Executed, sealed and delivered by
THE BANK OF NEW YORK and DOUGLAS J.
MACINNES in the presence of:

/s/ S. Eunice Kim
- ----------------------------------

/s/ Essie Elcock
- ----------------------------------



                                       15

STATE OF MINNESOTA                 )
                                   )  SS.:
COUNTY OF ST. LOUIS                )


         On this 15th day of April,  2005, before me, a Notary Public within and
for said County,  personally appeared JAMES K. VIZANKO and DEBORAH A. AMBERG, to
me personally  known,  who,  being each by me duly sworn,  did say that they are
respectively the Senior Vice President and Chief Financial  Officer and the Vice
President,  General  Counsel  and  Secretary  of  ALLETE,  INC.  of the State of
Minnesota,  the  corporation  named in the foregoing  instrument;  that the seal
affixed to the foregoing  instrument is the corporate seal of said  corporation;
that said  instrument  was signed and  sealed in behalf of said  corporation  by
authority  of its Board of  Directors;  and said JAMES K. VIZANKO and DEBORAH A.
AMBERG  acknowledged  said  instrument  to be the  free  act  and  deed  of said
corporation.

         Personally  came  before me on this 15th day of April,  2005,  JAMES K.
VIZANKO,  to me  known to be the  Senior  Vice  President  and  Chief  Financial
Officer,  and DEBORAH A. AMBERG,  to me known to be the Vice President,  General
Counsel and Secretary of the above NAMED ALLETE, INC., the corporation described
in and which executed the foregoing instrument, and to me personally known to be
the persons who as such officers  executed the foregoing  instrument in the name
and behalf of said  corporation,  who, being by me duly sworn did depose and say
and acknowledge  that they are  respectively the Senior Vice President and Chief
Financial Officer and the Vice President,  General Counsel and Secretary of said
corporation;  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 on  behalf  of said  corporation  by  authority  of its  Board of
Directors and stockholders, and said JAMES K. VIZANKO and DEBORAH A. AMBERG then
and  there  acknowledged  said  instrument  to be the  free act and deed of said
corporation and that such corporation executed the same.

         On the 15th day of April,  2005,  before me  personally  came  JAMES K.
VIZANKO and DEBORAH A. AMBERG,  to me known,  who,  being by me duly sworn,  did
depose and say that they respectively reside at 1340 Mississippi Avenue, Duluth,
Minnesota,  and  1923  West  Kent  Road,  Duluth,   Minnesota;   that  they  are
respectively  the  Vice  President  and  Chief  Financial  Officer  and the Vice
President,   General  Counsel  and  Secretary  of  ALLETE,   INC.,  one  of  the
corporations  described in and which  executed the above  instrument;  that they
know the seal of said  corporation;  that the seal affixed to said instrument is
such corporate  seal;  that it was so affixed by order of the Board of Directors
of said corporation, and that they signed their names thereto by like order.

         GIVEN under my hand and notarial seal this 15th day of April, 2005.



                                               /s/ Jodi M. Nash
                                      ------------------------------------------

           JODI M. NASH                              JODI M. NASH
     NOTARY PUBLIC - MINNESOTA                  NOTARY PUBLIC - MINNESOTA
My Commission Expires Jan. 31, 2010          My Commission Expires  1/31/2010
                                                                   -----------



                                       16

STATE OF NEW YORK                  )
                                   )  SS:
COUNTY OF NEW YORK                 )


         On this 19th day of April,  2005, before me, a Notary Public within and
for said  County,  personally  appeared  MING RYAN and  GEOVANNI  BARRIS,  to me
personally  known,  who,  being  each by me duly  sworn,  did say that  they are
respectively  a Vice  President and an Vice President of THE BANK OF NEW YORK of
the State of New York, the corporation named in the foregoing  instrument;  that
the seal  affixed to the  foregoing  instrument  is the  corporate  seal of said
corporation;  that  said  instrument  was  signed  and  sealed in behalf of said
corporation  by  authority  of its  Board of  Directors;  and said MING RYAN and
GEOVANNI BARRIS acknowledged said instrument to be the free act and deed of said
corporation.

         Personally  came before me on this 19th day of April,  2005, MING RYAN,
to me known to be a Vice  President,  and GEOVANNI  BARRIS,  to me known to be a
Vice  President,  of the  above  named  THE BANK OF NEW  YORK,  the  corporation
described in and which executed the foregoing  instrument,  and to me personally
known to be the persons who as such officers  executed the foregoing  instrument
in the name and  behalf of said  corporation,  who,  being by me duly  sworn did
depose and say and acknowledge that they are respectively a Vice President and a
Vice President of said corporation;  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 on  behalf of said  corporation  by
authority of its Board of Directors, and said MING RYAN and GEOVANNI BARRIS then
and  there  acknowledged  said  instrument  to be the  free act and deed of said
corporation and that such corporation executed the same.

         On the 19th day of April, 2005, before me personally came MING RYAN and
GEOVANNI  BARRIS,  to me known,  who, being by me duly sworn, did depose and say
that they respectively  reside at 19 Belaire Court,  Roseland,  NJ 07068, and 14
Huber Court,  Hightstown,  NJ 08520; that they are respectively a Vice President
and a Vice President of THE BANK OF NEW YORK, one of the corporations  described
in and  which  executed  the above  instrument;  that they know the seal of said
corporation;  that the seal affixed to said  instrument is such corporate  seal;
that it was so affixed by order of the Board of Directors  of said  corporation,
and that they signed their names thereto by like order.

         GIVEN under my hand and notarial seal this 19th day of April, 2005.






                                                   /s/ William J. Cassels
                                             -----------------------------------
                                               Notary Public, State of New York



                                                     William J. Cassels
                                              Notary Public, State of New York
                                                      No. 01CA5027729
                                                 Qualified in Bronx County
                                              Commission Expires May 18, 2006




                                       17


STATE OF NEW YORK                  )
                                   )  SS:
COUNTY OF NEW YORK                 )


         On this 19th day of April, 2005, before me personally  appeared DOUGLAS
J.  MACINNES,  to me known to be the person  described  in and who  executed the
foregoing instrument, and acknowledged that he executed the same as his free act
and deed.

         Personally came before me this 19th day of April, 2005, the above named
DOUGLAS J.  MACINNES,  to me known to be the person who executed  the  foregoing
instrument, and acknowledged the same.

         On the 19th day of April,  2005,  before me personally  came DOUGLAS J.
MACINNES,  to me  known  to be the  person  described  in and who  executed  the
foregoing instrument, and acknowledged that he executed the same.

         GIVEN under my hand and notarial seal this 19th day of April, 2005.




                                                   /s/ William J. Cassels
                                             -----------------------------------
                                               Notary Public, State of New York



                                                     William J. Cassels
                                              Notary Public, State of New York
                                                      No. 01CA5027729
                                                 Qualified in Bronx County
                                              Commission Expires May 18, 2006