Alton, IL -- U.S. city in Illinois Population (2000): 30496 Housing Units (2000): 13894 Land area (2000): 15.644983 sq. miles (40.520319 sq. km) Water area (2000): 0.960782 sq. miles (2.488413 sq. km) Total area (2000): 16.605765 sq. miles (43.008732 sq. km) FIPS code: 01114 Located within: Illinois (IL), FIPS 17 Location: 38.900438 N, 90.159844 W ZIP Codes (1990): 62002 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Alton, IL Alton