| Locality | Post Code |
|---|---|
| Albion, Calhoun | 49224 |
| Athens, Calhoun | 49011 |
| Battle Creek, Calhoun | 49014, 49015, 49017, 49037 |
| Bedford, Calhoun | 49020 |
| Bellevue, Calhoun | 49021 |
| Burlington, Calhoun | 49029 |
| Ceresco, Calhoun | 49033 |
| Climax, Calhoun | 49034 |
| East Leroy, Calhoun | 49051 |
| Fulton, Calhoun | 49052 |
| Homer, Calhoun | 49245 |
| Marshall, Calhoun | 49068 |
| Olivet, Calhoun | 49076 |
| Springfield, Calhoun | 49015, 49037 |
| Springport, Calhoun | 49284 |
| Tekonsha, Calhoun | 49092 |
| Union City, Calhoun | 49094 |