10 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 53538 | Fort Atkinson | 18,604 |
| 53094 | Watertown | 18,151 |
| 53549 | Jefferson | 9,901 |
| 53551 | Lake Mills | 9,485 |
| 53594 | Waterloo | 5,187 |
| 53038 | Johnson Creek | 4,319 |
| 53036 | Ixonia | 3,483 |
| 53156 | Palmyra | 3,314 |
| 53178 | Sullivan | 2,741 |
| 53137 | Helenville | 1,605 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 10 ZCTAs in Jefferson County, Wisconsin (US Census).