Macomb is a city in and the county seat of McDonough County, Illinois, United States. It is situated in western Illinois, southwest of Galesburg. The city is about 75 miles (121 km) southwest of Peoria and 77 miles (124 km) south of the Quad Cities. A special census held in 2014 placed the city's population at 21,516. Macomb is the home of Western Illinois University.
First settled in 1829 on a site tentatively named Washington, the town was officially founded in 1830 as the county seat of McDonough County and given the name Macomb after General Alexander Macomb, a general in the War of 1812. War veterans were given land grants in the Macomb area, which was part of the "Military Tract" set aside by Congress. In 1855 the Northern Cross Railroad, a predecessor to the Chicago, Burlington and Quincy Railroad, was constructed through Macomb, leading to a rise in the town's population. In 1899 the Western Illinois State Normal School, later Western Illinois University, was founded in Macomb. Representative Lawrence Sherman was instrumental in locating the school in Macomb.