Post Offices List in Lamar County, Mississippi:
| Hattiesburg Post Office | 220 S 40th Ave, Hattiesburg, MS 39402 |
| Lumberton Post Office | 7877 U S Highway 11, Lumberton, MS 39455 |
| Purvis Post Office | 5851 Us Highway 11, Purvis, MS 39475 |
| Sumrall Post Office | 4862 Highway 589, Sumrall, MS 39482 |