St Louis Utilities Holding Companies 1901 Chouteau Ave Ameren serves 2.4 million electric customers and one million natural gas customers in a 64,000-square-mile area of Missouri and Illinois. Site includes resources for home and business, links for investors and job seekers. St Louis MO Utilities Holding Companies Ameren Corp www.ameren.com ameren amerenue amerencips amerencilco amerenenergy amerenip ue cips cilco ip gas coal conservation deregulation regulated electric electricity emissions energy environmental hydroelectric generation greenhouse metering NOx nuclear power SO2 transmi ameren amerenue amerencips amerencilco amerenenergy amerenip ue cips cilco ip gas coal conservation deregulation regulated electric electricity emissions energy environmental hydroelectric generation greenhouse metering NOx nuclear power SO2 transmi Business Reviews Ameren Corp Testimonials