| Zip Code | City | Population ↓ |
|---|---|---|
| 29812 | Barnwell | 10,773 |
| 29853 | Williston | 6,205 |
| 29817 | Blackville | 4,392 |
| 29826 | Elko | 219 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 4 ZCTAs in Barnwell County, South Carolina (US Census).