Mitchell is a city in and the county seat of Davison County, South Dakota, United States. The population was 15,660 at the 2020 census makin…Mitchell is a city in and the county seat of Davison County, South Dakota, United States. The population was 15,660 at the 2020 census making it the sixth most populous city in South Dakota. Mitchell is the principal city of the Mitchell Micropolitan Statistical Area, which includes all of Davison and Hanson counties.