12 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 61081 | Sterling | 20,916 |
| 61071 | Rock Falls | 13,482 |
| 61270 | Morrison | 7,067 |
| 61252 | Fulton | 5,369 |
| 61277 | Prophetstown | 2,983 |
| 61250 | Erie | 2,843 |
| 61283 | Tampico | 1,349 |
| 61230 | Albany | 1,028 |
| 61261 | Lyndon | 691 |
| 61251 | Fenton | 336 |
| 61243 | Deer Grove | 167 |
| 61037 | Galt | 100 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 12 ZCTAs in Whiteside County, Illinois (US Census).