| Locality | Post Code |
|---|---|
| Davis City, Decatur | 50065 |
| Decatur City, Decatur | 50067 |
| Garden Grove, Decatur | 50103 |
| Grand River, Decatur | 50108 |
| High Point, Decatur | 50103 |
| Lamoni, Decatur | 50140 |
| Leon, Decatur | 50144 |
| Lineville, Decatur | 50147 |
| Pleasanton, Decatur | 50065 |
| Van Wert, Decatur | 50262 |
| Weldon, Decatur | 50264 |
| Westerville, Decatur | 50108 |
| Woodland, Decatur | 50103 |