| Locality | Post Code |
|---|---|
| Barnwell, Barnwell | 29812 |
| Blackville, Barnwell | 29817 |
| Elko, Barnwell | 29826 |
| Hilda, Barnwell | 29813 |
| Kline, Barnwell | 29812 |
| Martin, Barnwell | 29836 |
| Olar, Barnwell | 29843 |
| Snelling, Barnwell | 29812 |
| White Pond, Barnwell | 29853 |
| Williston, Barnwell | 29853 |