Large private utility serving central Illinois. Originally, a very diversified corporation providing electric, gas, ice and water service. Founded in Springfield in 1912.

Reports, photographic negatives and prints, charts, maps, notes, service area maps for various utilities, CIPS organizational charts, sales quotas, reports, telegrams, and research files documenting the sales policies, plans, and procedures of CIPS; its participation in award competitions; its research on other privately owned utilities in the Midwest; the extent of municipal and private electric service in Illinois; and all aspects of the company's operations for 1930. Topics include CIPS commercial and residential rates and sales; municipal elextric plants' rates and sales; and establishment and ownership of Illinois power plants. Of particular note are Municipal Utility Opposition Files, 1930-1941, consisting of clippings, wall posters, handbills, mass meeting reports, brochures, drafts of posters, articles and reports, handwritten notes, and a legal brief documenting the opposition of CIPS, as a corporate entity and under various pseudonyms, to the construction and operation of municipal utility plants in Auburn, Bushnell, Harrisburg, Herrin, and Petersburg. Results of some local municipal utility referenda; typescript summaries of meetings held in favor of municipal utility plants; and a CIPS vs. City of Bushnell legal brief are included.