TWENTY-EIGHTH SUPPLEMENTAL INDENTURE

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

THIS INDENTURE , dated as of May 1, 2008, 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 call 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 (Douglas J. MacInnes, successor Co-Trustee), 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-eighth 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

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:

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

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

which bonds are also hereinafter sometimes called bonds of the First through Thirty-third 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 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-eighth Supplemental Indenture, and the terms of the bonds of the Thirty-fourth Series, hereinafter referred to, have been duly authorized by the Board of Directors of the Company by appropriate resolutions of said Board of Directors;

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 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-eighth 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, pledged, set over or confirmed hereunder and are hereby expressly excepted from the lien and operation of this Twenty-eighth 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-eighth 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 o