| Locality | Post Code |
|---|---|
| Auburn, Calhoun | 51433 |
| Farnhamville, Calhoun | 50538 |
| Fonda, Calhoun | 50540 |
| Jolley, Calhoun | 50551 |
| Knierim, Calhoun | 50552 |
| Knoke, Calhoun | 50575 |
| Lake City, Calhoun | 51449 |
| Lanedale, Calhoun | 50579 |
| Lavinia, Calhoun | 50579 |
| Lohrville, Calhoun | 51453 |
| Lytton, Calhoun | 50561 |
| Manson, Calhoun | 50563 |
| Piper, Calhoun | 50579 |
| Pomeroy, Calhoun | 50575 |
| Rands, Calhoun | 50579 |
| Richards, Calhoun | 50579 |
| Rinard, Calhoun | 50538 |
| Rockwell City, Calhoun | 50579 |
| Sherwood, Calhoun | 50579 |
| Somers, Calhoun | 50586 |
| Wieston, Calhoun | 50563 |