Hamilton County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 15,039, and was estimated to be 14,944 in 2025. The county was named to honor William W. Hamilton, a President of the Iowa State Senate.
Geography
According to the United States Census Bureau, the county has a total area of , of which is land and (0.13%) is water. It is the 36th largest county in Iowa by total area. The largest body of water is Little Wall Lake.
Major highways
- x20px Interstate 35
- x20px U.S. Highway 20
- x20px U.S. Highway 69
- x20px Iowa Highway 17
- x20px Iowa Highway 175
Transit
Adjacent counties
- Wright County (north)
- Hardin County (east)
- Story County (southeast)
- Boone County (southwest)
- Webster County (west)