Sigourney is a city and the county seat of Keokuk County, Iowa, United States. The population was 2,004 at the time of the 2020 census. Ke…Sigourney is a city and the county seat of Keokuk County, Iowa, United States. The population was 2,004 at the time of the 2020 census. Keokuk County Courthouse is located in the Public Square Historic District. Both are on the National Register of Historic Places.