Macomb is located in western Illinois in McDonough County (of which it is the county seat) southwest of Galesburg along U.S. Highway 136 east of the LaMoine River. It was established in 1830 and is named in honor of a War of 1812 hero.

Macomb is home to Western Illinois University which was founded in 1899. The St Louis Rams of the National Football League conduct their 3-week pre-season training camp on the campus beginning in late July.

Points of interest: Macomb and McDonough County have a number of historically significant barns including an unusual "True-Round" and variations of the "Crossgable"-style of barn and is unique to the area.

Argyle Lake State Park provides 1,700 acres of recreational oppportunities for park visitors including boating and fishing on 93-acre Argyle Lake. In addition, golfers will want to challenge Harry Mussatto Golf Course.

The population estimate for July 1, 1998 was 17,778, a decrease of 2,174 since 1990.