Marshall County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 40,105, and was estimated to be 39,890 in 2025. The county was formed on January 13, 1846, and named after John Marshall, Chief Justice of the United States Supreme Court. Marshall County comprises the Marshalltown, Iowa Micropolitan Statistical Area. In 2010, the center of population of Iowa was located in Marshall County, near Melbourne.
Geography
According to the United States Census Bureau, the county has a total area of , of which is land and (0.12%) is water. It is the 43rd largest county in Iowa by total area.
Transit
- Marshalltown Municipal Transit
Major highways
Adjacent counties
- Jasper County (South)
- Tama County (East)
- Story County (West)
- Hardin County (Northwest)
- Grundy County (North)