Post Offices List in Barnwell City, South Carolina:
| Barnwell Post Office | 221 Main St, Barnwell, SC 29812 |
| Hilda Post Office | 75 Railroad Ave, Barnwell, SC 29812 |
| Barnwell Post Office | 221 Main St, Barnwell, SC 29812 |
| Hilda Post Office | 75 Railroad Ave, Barnwell, SC 29812 |