| Localité | Code postal |
|---|---|
| Aurora, Buchanan | 50607 |
| Brandon, Buchanan | 52210 |
| Coggon, Buchanan | 52218 |
| Doris, Buchanan | 50644 |
| Fairbank, Buchanan | 50629 |
| Hazleton, Buchanan | 50641 |
| Independence, Buchanan | 50644 |
| Jesup, Buchanan | 50648 |
| Lamont, Buchanan | 50650 |
| Littleton, Buchanan | 50648 |
| Masonville, Buchanan | 50654 |
| Otterville, Buchanan | 50644 |
| Quasqueton, Buchanan | 52326 |
| Rowley, Buchanan | 52329 |
| Shady Grove, Buchanan | 50648 |
| Stanley, Buchanan | 50671 |
| Walker, Buchanan | 52352 |
| Winthrop, Buchanan | 50682 |