Marion County Iowa (Historic Districts) has 4 places on the National Register of Historic Places including 1 place of Statewide significance. Significant places include Knoxville WPA Athletic Field Historic District, Knoxville WPA Athletic Field Historic District, St. Joseph's Roman Catholic Church and Cemetery Historic District.
Some of the country's most noteable architects helped create the Marion County places including Works Progress Administration. Prominent architectural styles found in Marion Country are Classical Revival, Colonial Revival and Late Gothic Revival.