Founded in 1873, Lyman County is one of 66 counties in the state of South Dakota. Historically, Lyman County was formed from unorganized territory. The city of Kennebec is the county seat. With FIPS code of 85, Lyman County has a population of 3,764 and area of 1,640 square miles (4,248 km2).
List of all cities in Lyman County, SD alphabetically
| City/Town | Postal Code | Area Code |
| Edna, SD | 57568 | 605 |
| Grass Rope, SD | 57569 | 605 |
| Hilmoe, SD | 57568 | 605 |
| Houston, SD | 57544 | 605 |
| Iron Mountain, SD | 57544 | 605 |
| Kennebec, SD | 57544 | 605 |
| Lower Brule, SD | 57548 | 605 |
| Lyman, SD | 57569 | 605 |
| McClure, SD | 57576 | 605 |
| Oacoma, SD | 57365 | 605 |
| Presho, SD | 57568 | 605 |
| Reliance, SD | 57569 | 605 |
| Sweeney, SD | 57568 | 605 |
| Vivian, SD | 57576 | 605 |