Seneca, MO -- U.S. city in Missouri Population (2000): 2135 Housing Units (2000): 876 Land area (2000): 1.734021 sq. miles (4.491094 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 1.734021 sq. miles (4.491094 sq. km) FIPS code: 66674 Located within: Missouri (MO), FIPS 29 Location: 36.840318 N, 94.609918 W ZIP Codes (1990): 64865 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Seneca, MO Seneca