10 ZIP Codes
| Zip Code | City | Population ↓ |
|---|---|---|
| 53538 | Fort Atkinson | 18,813 |
| 53094 | Watertown | 17,998 |
| 53549 | Jefferson | 9,873 |
| 53551 | Lake Mills | 9,731 |
| 53594 | Waterloo | 5,199 |
| 53038 | Johnson Creek | 4,192 |
| 53036 | Ixonia | 3,730 |
| 53156 | Palmyra | 3,232 |
| 53178 | Sullivan | 2,497 |
| 53137 | Helenville | 1,650 |
The data shown reflect ZCTAs from the US Census. As of 2025, there are 10 ZCTAs in Jefferson County, Wisconsin (US Census).