Louisa -- U.S. County in Iowa Population (2000): 12183 Housing Units (2000): 5133 Land area (2000): 401.916979 sq. miles (1040.960153 sq. km) Water area (2000): 15.727962 sq. miles (40.735233 sq. km) Total area (2000): 417.644941 sq. miles (1081.695386 sq. km) Located within: Iowa (IA), FIPS 19 Location: 41.217443 N, 91.261679 W Headwords: Louisa Louisa, IA Louisa County Louisa County, IA