Geneseo, IL -- U.S. city in Illinois Population (2000): 6480 Housing Units (2000): 2854 Land area (2000): 4.032439 sq. miles (10.443969 sq. km) Water area (2000): 0.008036 sq. miles (0.020813 sq. km) Total area (2000): 4.040475 sq. miles (10.464782 sq. km) FIPS code: 28846 Located within: Illinois (IL), FIPS 17 Location: 41.449915 N, 90.153347 W ZIP Codes (1990): 61254 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Geneseo, IL Geneseo