Farmington, IL -- U.S. city in Illinois Population (2000): 2601 Housing Units (2000): 1114 Land area (2000): 1.241440 sq. miles (3.215314 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 1.241440 sq. miles (3.215314 sq. km) FIPS code: 25531 Located within: Illinois (IL), FIPS 17 Location: 40.698855 N, 90.003673 W ZIP Codes (1990): Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Farmington, IL Farmington