Fairmount, IL -- U.S. village in Illinois Population (2000): 640 Housing Units (2000): 280 Land area (2000): 0.311379 sq. miles (0.806468 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 0.311379 sq. miles (0.806468 sq. km) FIPS code: 24985 Located within: Illinois (IL), FIPS 17 Location: 40.045124 N, 87.829879 W ZIP Codes (1990): 61841 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Fairmount, IL Fairmount