Founded in 1798, Barnwell County is one of 46 counties in the state of South Carolina. Historically, Barnwell County was formed from Orangeburg. The city of Barnwell is the county seat. With FIPS code of 11, Barnwell County has a population of 20,580 and area of 557 square miles (1,443 km2).
List of all cities in Barnwell County, SC alphabetically
| City/Town | Postal Code | Area Code |
| Barnwell, SC | 29812 | 803 |
| 29813 | 803 | |
| Blackville, SC | 29817 | 803 |
| Elko, SC | 29826 | 803 |
| Hilda, SC | 29813 | 803 |
| Kline, SC | 29812 | 803 |
| Snelling, SC | 29812 | 803 |
| White Pond, SC | 29853 | 803 |
| Williston, SC | 29853 | 803 |