Monticello, IA -- U.S. city in Iowa Population (2000): 3607 Housing Units (2000): 1637 Land area (2000): 3.677666 sq. miles (9.525112 sq. km) Water area (2000): 0.023185 sq. miles (0.060048 sq. km) Total area (2000): 3.700851 sq. miles (9.585160 sq. km) FIPS code: 53625 Located within: Iowa (IA), FIPS 19 Location: 42.238759 N, 91.189067 W ZIP Codes (1990): 52310 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Monticello, IA Monticello