| Locality | Post Code |
|---|---|
| Baldwin, Harrison | 75661 |
| Blocker, Harrison | 75670 |
| Cave Springs, Harrison | 75670 |
| Darco, Harrison | 75670 |
| Elysian Fields, Harrison | 75642 |
| Gill, Harrison | 75670 |
| Grange Hall, Harrison | 75670 |
| Hallsville, Harrison | 75650 |
| Harleton, Harrison | 75651 |
| Jonesville, Harrison | 75659 |
| Karnack, Harrison | 75661 |
| Leigh, Harrison | 75661 |
| Marshall, Harrison | 75670, 75672 |
| Nesbitt, Harrison | 75670 |
| Scottsville, Harrison | 75688 |
| Uncertain, Harrison | 75661 |
| Walkers Mill, Harrison | 75650 |
| Waskom, Harrison | 75692 |
| Woodlawn, Harrison | 75694 |