Frontenac, MO -- U.S. city in Missouri Population (2000): 3483 Housing Units (2000): 1360 Land area (2000): 2.851871 sq. miles (7.386311 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 2.851871 sq. miles (7.386311 sq. km) FIPS code: 26110 Located within: Missouri (MO), FIPS 29 Location: 38.633752 N, 90.417901 W ZIP Codes (1990): Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Frontenac, MO Frontenac