Ameren Illinois Company

Ameren Illinois (AILIH) is an Illinois-based, rate-regulated utility that manages the generation, transmission, and distribution of electricity, as well as the distribution of natural gas. Serving a vast 43,700 square-mile region across central and eastern Illinois, the company supplies electricity to 1.2 million customers and natural gas to 0.8 million customers. Established in 1902 and headquartered in Collinsville, Illinois, the company was formerly known as Central Illinois Public Service Company before rebranding as Ameren Illinois Company in October 2010. It operates as a subsidiary of Ameren Corporation.