Mount Vernon, IA -- U.S. city in Iowa Population (2000): 3390 Housing Units (2000): 1192 Land area (2000): 3.483918 sq. miles (9.023307 sq. km) Water area (2000): 0.006246 sq. miles (0.016176 sq. km) Total area (2000): 3.490164 sq. miles (9.039483 sq. km) FIPS code: 54840 Located within: Iowa (IA), FIPS 19 Location: 41.924096 N, 91.419679 W ZIP Codes (1990): 52314 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Mount Vernon, IA Mount Vernon