Decatur, Illinois, the seat of Macon County. It is in the central part of the state on the Sangamon River, 170 miles (275 km) southwest of Chicago. The city is the center of a coal-mining and agricultural region. Decatur has corn and soybean processing plants and produces construction equipment, tires, castings, machinery, and plumbing equipment.

Decatur was the first Illinois home of Abraham Lincoln. The log-cabin courthouse where he practiced law is preserved in a park. Millikin University, founded in 1903, is here. Decatur was settled in 1829 and was named after Commodore Stephen Decatur. The Grand Army of the Republic, the Union veterans' organization of the Civil War, was founded here in 1866.

Population: 81,860.