CIPS was founded in 1902 and appears to have taken over power in Marion when they purchase the local grid around 1912.
In 1917, CIPS acquired the turbine generating plant at Muddy and had already built a transmission line. This enabled the company to take on the heavy mine loads in the area which previously had been avoided due to lack of generating capacity. This added mine related load brought about rapid growth for the company and necessitated the 1923 construction of a modern plant at Grand Tower Illinois along the Mississippi River in Jackson County.
In this time period through 1927, CIPS maintained an office at 802 Public Square over Bainbridge Jewelry next to the Orpheum. In September 1927, they occupied a large building at 202-204 East Main Street across the street from the Post Office which served as offices and warehousing for local service and the Southern Division. The building was originally built by the Elles Store Co. and housed their Marion Supply Company. This office building location was in service for about forty years. In October 1968 construction was begun on a new Marion Group and Southern Division Office building at 1800 W. Main Street. It was moved into July 1970 and became functional as the Southern Division office in August 1971.
By 1927, CIPS had purchased Cambria Light and Service Company and the municipal system in Creal Springs thereby serving Blairsville, Cambria, Pittsburg and Creal with electricity.
Around 1970, CIPS served 25 Williamson County communities with electricity and 15 with natural gas. The communities were served by 34 employees in the CIPS Marion Area office and 18 employees in the Herrin district. In addition, Marion played a major role as headquarters for the Southern Division, an area which covered much of Southern Illinois.
In 1970, CIPS produced electricity for its customers at its five generating stations, the newest of which was completed in 1982. All of the stations burned coal to generate electricity. The entire CIPS system covered more than 20,000 square miles in Central and Southern Illinois, with electric service provided in 557 communities and natural gas service in 261 communities.
Ameren Corporation was created by the December 1997 merger of CIPSCO Incorporated, the parent company of Central Illinois Public Service, and Union Electric Company. In 2004, Ameren acquired Illinois Power Company – and operated as AmerenIP.
Ameren Illinois was formed October 1, 2010 consolidating Ameren CIPS, Ameren CILCO and Ameren IP (Illinois Power).
In 2013, Ameren Illinois serves 1.2 million electric and 813,000 natural-gas customers in more than 1,200 communities within a 43,700 square-mile territory. The complex Ameren delivery system includes about 4,500 miles of transmission lines, 45,400 miles of distribution lines, 18,000 miles of natural gas transmission and distribution mains, and 12 underground natural gas storage fields.
(Data from Marion Daily Republican History Progress Edition, Ameren.com, Marion, Illinois Business Directories; compiled by Sam Lattuca on 01/28/2013)