St. John, MO -- U.S. city in Missouri Population (2000): 6871 Housing Units (2000): 2978 Land area (2000): 1.423820 sq. miles (3.687677 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 1.423820 sq. miles (3.687677 sq. km) FIPS code: 64478 Located within: Missouri (MO), FIPS 29 Location: 38.716151 N, 90.345826 W ZIP Codes (1990): Note: some ZIP codes may be omitted esp. for suburbs. Headwords: St. John, MO St. John