St. Louis, city, adjacent to but independent of St. Louis county, east-central Missouri, U.S. It lies on the west bank of the Mississippi River (bridged there at several points) opposite East St. Louis, Illinois, just south of the confluence of the Missouri River. The city’s boundaries have remained unchanged since 1876, when it became administratively independent. It is, however, the state’s largest and most populous metropolitan area. Suburban communities include Chesterfield, Florissant, Kirkwood, St. Charles, and University City in Missouri and Alton, Belleville, East St. Louis, and Granite City in Illinois. Inc. town, 1809; city, 1822. Area city, 66 square