About Ameren

Every day, Ameren is working hard to provide more reliable energy, reduce outages and restore power faster than ever before. It's all part of our ongoing commitment to keep pace with future energy needs, as we proudly continue to serve, support and invest in the communities we call home.


Energy At Work

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Residential Rates


View the Ameren Sustainability Report
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Facts and Figures

Ameren Corporation is a Fortune 500 company that trades on the New York Stock Exchange under the symbol AEE. It is the parent company of Ameren Illinois, based in Collinsville, Ill., and Ameren Missouri in St. Louis. Ameren Transmission Company, also based in St. Louis, designs and builds regional transmission projects.

Ameren was created by the combination of three Illinois utilities (CIPSCO Incorporated, CILCO Inc. and Illinois Power Company) and Union Electric Company of St. Louis. The name comes from combining the words American and Energy. 

Employing more than 9,000 personnel, Ameren powers the quality of life for 2.4 million electric customers and more than 900,000 natural gas customers across a 64,000-square-mile area. 

Ameren Missouri ranks as the largest electric power provider in Missouri, and Ameren Illinois ranks as Illinois' third largest natural gas distribution operation in total number of customers. 

Ameren companies generate a net capacity of nearly 10,200 megawatts of electricity and own more than 7,500 circuit miles of transmission lines.

Ameren's rates are some of the lowest in the nation. View our Ameren Missouri and Ameren Illinois rates.

Find more in the Ameren Fact Sheet (PDF).

Vision, Mission & Values


Leading the way to a sustainable energy future.


To power the quality of life.


Our values - the way we do business - include safety, integrity, respect, diversity, equity and inclusion, accountability, stewardship, teamwork and commitment to excellence.

Ameren Company History

Ameren Corporation was formed in 1997 by the merger of Missouri’s Union Electric Company with neighboring Central Illinois Public Service Company - but our roots stretch back to 1902. We’re proud of our long, successful tradition of financial strength, low rates and pride in customer service. Key dates in our century-long history includes:
Ameren subsidiaries Illinois Power, CIPS and Cilco merge into Ameren Illinois, while AmerenUE changes its name to Ameren Missouri. Ameren Transmission Company is formed.
Ameren acquires Illinois Power.
Ameren acquires CILCORP Inc.
Union Electric and CIPSCO, Inc. merge to create Ameren Corporation.
Union Electric produces nuclear energy for the first time when the Callaway Plant begins generating 1,143 megawatts of power.
CIPSCO joins with Illinois Power and Union Electric to form the Midwest Power Pool system.
“Bagnell Damming” the Osage River is successful, generating almost 175 megawatts of hydroelectricity at Union Electric’s Osage Plant and creating the popular Lake of the Ozarks.
Union Company “electrifies” the St. Louis World Fair - the nation’s first broad-scale demonstration of power.
Union Company (later Union Electric) is formed in St. Louis, Mo., and Central Illinois Public Service Company (later CIPSCO) begins life as the Mattoon City Railway Streetcar.