Founded in 1873, Campbell County is one of 66 counties in the state of South Dakota. Historically, Campbell County was formed from Buffalo County. The city of Mound City is the county seat. With FIPS code of 21, Campbell County has a population of 1,380 and area of 736 square miles (1,906 km2).
List of all cities in Campbell County, SD alphabetically
| City/Town | Postal Code | Area Code |
| Campbell, SD | 57646 | 605 |
| Herreid, SD | 57632 | 605 |
| Mound City, SD | 57646 | 605 |
| Pollock, SD | 57648 | 605 |