Founded in 1879, Day County is one of 66 counties in the state of South Dakota. Historically, Day County was formed from Clark County. The city of Webster is the county seat. With FIPS code of 37, Day County has a population of 5,414 and area of 1,029 square miles (2,665 km2).
List of all cities in Day County, SD alphabetically
| City/Town | Postal Code | Area Code |
| Andover, SD | 57422 | 605 |
| Blue Dog Lake, SD | 57273 | 605 |
| Bristol, SD | 57219 | 605 |
| Butler, SD | 57219 | 605 |
| Grenville, SD | 57239 | 605 |
| Holmquist, SD | 57274 | 605 |
| Lily, SD | 57274 | 605 |
| Pierpont, SD | 57468 | 605 |
| Roslyn, SD | 57261 | 605 |
| Waubay, SD | 57273 | 605 |
| Webster, SD | 57274 | 605 |