12 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 61081 | Sterling | 21,138 |
| 61071 | Rock Falls | 13,766 |
| 61270 | Morrison | 7,096 |
| 61252 | Fulton | 5,424 |
| 61277 | Prophetstown | 2,978 |
| 61250 | Erie | 2,713 |
| 61283 | Tampico | 1,422 |
| 61230 | Albany | 932 |
| 61261 | Lyndon | 644 |
| 61251 | Fenton | 382 |
| 61243 | Deer Grove | 277 |
| 61037 | Galt | 105 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 12 ZCTAs in Whiteside County, Illinois (US Census).