12 ZIP Codes
| Zip Code | City | Population ↓ |
|---|---|---|
| 61081 | Sterling | 20,844 |
| 61071 | Rock Falls | 13,581 |
| 61270 | Morrison | 6,912 |
| 61252 | Fulton | 5,437 |
| 61277 | Prophetstown | 3,054 |
| 61250 | Erie | 2,781 |
| 61283 | Tampico | 1,269 |
| 61230 | Albany | 1,039 |
| 61261 | Lyndon | 656 |
| 61251 | Fenton | 377 |
| 61243 | Deer Grove | 155 |
| 61037 | Galt | 145 |
The data shown reflect ZCTAs from the US Census. As of 2025, there are 12 ZCTAs in Whiteside County, Illinois (US Census).