| Locality | Post Code |
|---|---|
| Alvada, Seneca | 44802 |
| Amsden, Seneca | 44830 |
| Attica, Seneca | 44807 |
| Attica Junction, Seneca | 44807 |
| Bascom, Seneca | 44809 |
| Berwick, Seneca | 44853 |
| Bettsville, Seneca | 44815 |
| Bloomville, Seneca | 44818 |
| Buckeye Village, Seneca | 44807 |
| Caroline, Seneca | 44807 |
| Carrothers, Seneca | 44807 |
| Flat Rock, Seneca | 44828 |
| Fort Seneca, Seneca | 44883 |
| Fostoria, Seneca | 44830 |
| Green Springs, Seneca | 44836 |
| Ink, Seneca | 44883 |
| Kansas, Seneca | 44841 |
| Lykens, Seneca | 44818 |
| Melmore, Seneca | 44845 |
| New Riegel, Seneca | 44853 |
| Old Fort, Seneca | 44861 |
| Reed, Seneca | 44807 |
| Reedtown, Seneca | 44807 |
| Republic, Seneca | 44867 |
| Siam, Seneca | 44807 |
| Tiffin, Seneca | 44883 |