Exhibit 4.9

WHEN RECORDED MAIL TO :
Illinois Power Company
Craig W. Stensland

One Ameren Plaza (MC 1310)
1901 Chouteau Avenue

St. Louis, MO 63103

ILLINOIS POWER COMPANY

TO

THE BANK OF NEW YORK TRUST COMPANY, N.A.

(FORMERLY BNY MIDWEST TRUST COMPANY),

AS SUCCESSOR TRUSTEE TO

HARRIS TRUST AND SAVINGS BANK

SUPPLEMENTAL INDENTURE

DATED AS OF APRIL 1, 2008

TO

GENERAL MORTGAGE INDENTURE AND DEED OF TRUST

DATED AS OF NOVEMBER 1, 1992

This instrument was prepared by Steven R. Sullivan, Senior Vice President, General Counsel and Secretary of Illinois Power Company c/o Ameren Corporation, One Ameren Plaza, 1901 Chouteau Avenue, St. Louis, Missouri 63103.

SUPPLEMENTAL INDENTURE dated as of April 1, 2008 (“Supplemental Indenture”), made by and between ILLINOIS POWER COMPANY, a corporation organized and existing under the laws of the State of Illinois (the “Company”), party of the first part, and THE BANK OF NEW YORK TRUST COMPANY, N.A. (formerly BNY Midwest Trust Company), a corporation organized and existing under the laws of the State of Illinois, as successor trustee to Harris Trust and Savings Bank, a corporation organized and existing under the laws of the State of Illinois (the “Trustee”), as Trustee under the General Mortgage Indenture and Deed of Trust dated as of November 1, 1992, hereinafter mentioned, party of the second part;

WHEREAS , the Company has heretofore executed and delivered its General Mortgage Indenture and Deed of Trust dated as of November 1, 1992 as from time to time amended (the “Indenture”), to the Trustee, for the security of the Bonds of the Company issued and to be issued thereunder (the “Bonds”); and

WHEREAS , pursuant to the terms and provisions of the Indenture there were created and authorized by supplemental indentures thereto bearing the following dates, respectively, the Mortgage Bonds of the series issued thereunder and respectively identified opposite such dates:

and

WHEREAS , a supplemental indenture with respect to the Bonds of the 2007 Series and the Bonds of the 2012 Series listed above was executed and filed but such Bonds of the 2007 Series and Bonds of the 2012 Series were never issued and a release with respect to such supplemental indenture was subsequently executed and filed; and

2

WHEREAS , the Company desires to create a new series of Bonds to be issued under the Indenture to be known as “Mortgage Bonds, Senior Notes Series CC” (the “Series CC Mortgage Bonds”); and

WHEREAS , the Company has entered into an Indenture dated as of June 1, 2006 (the “Senior Note Indenture”) with The Bank of New York Trust Company, N.A., as trustee (the “Senior Note Trustee”), providing for the issuance from time to time of senior notes thereunder; and

WHEREAS , the Company desires by this Supplemental Indenture to issue to the Senior Note Trustee the Series CC Mortgage Bonds as security for $337,000,000 aggregate principal amount of the Company’s 6.25% Senior Secured Notes due 2018 (the “Senior Notes”) to be issued under the Senior Note Indenture; and

WHEREAS , the Company, in the exercise of the powers and authority conferred upon and reserved to it under the provisions of the Indenture, and pursuant to appropriate resolutions of the Board of Directors, has duly resolved and determined to make, execute and deliver to the Trustee this Supplemental Indenture in the form hereof for the purposes herein provided; and

WHEREAS , all conditions and requirements necessary to make this Supplemental Indenture a valid, binding and legal instrument have been done, performed and fulfilled and the execution and delivery hereof have been in all respects duly authorized;

NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH:

THAT Illinois Power Company, in consideration of the purchase and ownership from time to time of the Bonds and the service by the Trustee, and its successors, under the Indenture 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, hereby covenants and agrees to and with the Trustee and its successors in the trust under the Indenture, for the benefit of those who shall hold the Bonds as follows:

ARTICLE I

DESCRIPTION OF THE SERIES CC MORTGAGE BONDS.

Section 1.     The Company hereby creates a new series of Bonds to be known as “Mortgage Bonds, Senior Notes Series CC” (the “Series CC Mortgage Bonds”).  The Series CC Mortgage Bonds shall be executed, authenticated and delivered in accordance with the provisions of, and shall in all respects be subject to, all of the terms, conditions and covenants of the Indenture, as supplemented and modified.  The Series CC Mortgage Bonds shall be issued in the name of the Senior Note Trustee under the Senior Note Indenture to secure any and all of the Company’s obligations under the Senior Notes and any other series of senior notes from time to time outstanding under the Senior Note Indenture.

The Series CC Mortgage Bonds shall be dated as provided in Section 3.03 of Article Three of the Indenture.  The Series CC Mortgage Bonds shall mature on April 1, 2018, shall accrue interest from the dates set forth in the Senior Notes and shall bear interest at the same rate of interest as the Senior Notes.  Interest on the Series CC Mortgage Bonds is payable on the same dates as interest on the Senior Notes is paid, until the principal sum is paid in full.

3

Upon any payment of the principal of, premium, if any, and interest on, all or any portion of the Senior Notes, whether at maturity or prior to maturity by redemption or otherwise or upon provision for the payment thereof having been made in accordance with Section 5.01(a) of the Senior Note Indenture, the Series CC Mortgage Bonds in a principal amount equal to the principal amount of such Senior Notes shall, to the extent of such payment of principal, premium, if any, and interest, be deemed paid and the obligation of the Company thereunder to make such payment shall be discharged to such extent and, in the case of the payment of principal (and premium, if any), such Series CC Mortgage Bonds shall be surrendered to the Company for cancellation as provided in Section 4.08 of the Senior Note Indenture.  The Trustee may at any time and all times conclusively assume that the obligation of the Company to make payments with respect to the principal of, premium, if any, and interest on the Senior Notes, so far as such payments at the time have become due, has been fully satisfied and discharged pursuant to the foregoing sentence unless and until the Trustee shall have received a written notice from the Senior Note Trustee signed by one of its officers stating (i) the timely payment of principal, or premium, if any, or interest on, the Senior Notes has not been made, (ii) that the Company is in arrears as to the payments required to be made by it to the Senior Note Trustee pursuant to the Senior Note Indenture, and (iii) the amount of the arrearage.

Section 2.     The Series CC Mortgage Bonds and the Trustee’s Certificate of Authentication shall be substantially in the following forms respectively:

[FORM OF FACE OF BOND]

NOTWITHSTANDING ANY PROVISIONS HEREOF OR IN THE INDENTURE THIS BOND IS NOT ASSIGNABLE OR TRANSFERABLE EXCEPT AS PERMITTED BY SECTION 4.04 OF THE
INDENTURE DATED AS OF JUNE 1, 2006, BETWEEN
ILLINOIS POWER COMPANY AND THE BANK OF NEW YORK TRUST COMPANY, N.A., AS TRUSTEE

ILLINOIS POWER COMPANY

(Incorporated under the laws of the State of Illinois)

Illinois Commerce Commission
Identification No.: Ill. C.C. 6480

MORTGAGE BOND, SENIOR NOTES SERIES CC

ILLINOIS POWER COMPANY, a corporation organized and existing under the laws of the State of Illinois (the “Company”), which term shall include any successor corporation as defined in the Indenture hereinafter referred to, for value received, hereby promises to pay to The Bank of New York Trust Company, N.A., as trustee (the “Senior Note Trustee”) under the Indenture dated as of June 1, 2006 (the “Senior Note Indenture”), relating to the C