| Locality | Post Code |
|---|---|
| Beloit, Winnebago | 61080 |
| Cherry Valley, Winnebago | 61016 |
| Durand, Winnebago | 61024 |
| Irene, Winnebago | 61016 |
| Loves Park, Winnebago | 61111, 61115 |
| Machesney Park, Winnebago | 61103, 61111, 61115 |
| Morristown, Winnebago | 61109 |
| New Milford, Winnebago | 61109 |
| Pecatonica, Winnebago | 61063 |
| Rockford, Winnebago | 61101, 61102, 61103, 61104, 61107, … |
| Rockton, Winnebago | 61072 |
| Roscoe, Winnebago | 61073 |
| Seward, Winnebago | 61077 |
| Shirland, Winnebago | 61079 |
| South Beloit, Winnebago | 61080 |
| Winnebago, Winnebago | 61088 |