Decatur is a city in the American state of Illinois. In the 2000 census, there were more than 80,000 people living in it. Many people drive in and out of Decatur on Interstate 72. There is a shopping mall in nearby Forsyth, a suburb of Decatur.
Decatur is the county seat of Macon County. Macon County was the home of the young Abraham Lincoln, later U.S. president, for a short time. The place where the Lincoln family built a log cabin and spent the winter of 1829-1830 is now a state park, the "Lincoln Trail Homestead State Park."