Winthrop, IA -- U.S. city in Iowa Population (2000): 772 Housing Units (2000): 341 Land area (2000): 0.580075 sq. miles (1.502388 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 0.580075 sq. miles (1.502388 sq. km) FIPS code: 86565 Located within: Iowa (IA), FIPS 19 Location: 42.472419 N, 91.735713 W ZIP Codes (1990): 50682 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Winthrop, IA Winthrop