| Locality | Postal Code |
|---|---|
| Bridgewater, McCook | 57319 |
| Canistota, McCook | 57012 |
| Center, McCook | 57058 |
| Montrose, McCook | 57048 |
| Ramsey, McCook | 57048 |
| Rumpus Ridge, McCook | 57012 |
| Salem, McCook | 57058 |
| Silver Lake, McCook | 57319 |
| Spencer, McCook | 57374 |
| Stanley Corner, McCook | 57319 |
| Unityville, McCook | 57058 |