Decatur /dəˈkeɪtər/ is the largest city and the county seat of Macon County in the U.S. state of Illinois. The city was founded in 1829 and is located along the Sangamon River and Lake Decatur in Central Illinois. In 2013 the city population was 74,710.
The city is home of private Millikin University and public Richland Community College. Decatur has vast industrial and agricultural processing production, including the U.S. headquarters of international agricultural conglomerate Archer Daniels Midland, international agribusiness Tate & Lyle's largest corn-processing plant, and the designing and manufacturing facilities for Caterpillar Inc.'s wheel-tractor scrapers, off-highway trucks, and large mining trucks.