13 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 53511 | Beloit | 48,701 |
| 53546 | Janesville | 29,867 |
| 53545 | Janesville | 24,703 |
| 53548 | Janesville | 19,916 |
| 53534 | Edgerton | 12,241 |
| 53563 | Milton | 11,280 |
| 53536 | Evansville | 9,547 |
| 53520 | Brodhead | 6,687 |
| 53525 | Clinton | 4,066 |
| 53576 | Orfordville | 2,131 |
| 53537 | Footville | 752 |
| 53505 | Avalon | 358 |
| 53501 | Afton | 165 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 13 ZCTAs in Rock County, Wisconsin (US Census).