Downers Grove, village, DuPage County, northeastern Illinois, a suburb of Chicago; incorporated 1873. Manufactures include scientific and medical instruments, communications equipment, cleaning products, and processed food. Chicago College of Osteopathic Medicine (1900) is here, and Morton Arboretum and Argonne National Laboratory are nearby. The village is named for its founder, Pierce Downer, who settled here in 1832. Population 42,572 (1980); 46,858 (1990); 48,724 (2000).