There are 34 cities in Jefferson County, Wisconsin.
Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Population | 2020 Population | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Janesville | 1 | 66,246 | 65,670 | 0.22% | 1,924 | 34.4 | City |
| Watertown | 2 | 22,611 | 22,935 | -0.36% | 1,874 | 12.1 | City |
| Oconomowoc | 3 | 18,827 | 18,245 | 0.78% | 1,601 | 11.8 | City |
| Whitewater | 4 | 15,458 | 16,134 | -1.08% | 1,749 | 8.8 | City |
| Fort Atkinson | 5 | 12,273 | 12,581 | -0.62% | 2,099 | 5.8 | City |
| Jefferson | 6 | 7,593 | 7,805 | -0.69% | 1,302 | 5.8 | City |
| Delafield | 7 | 7,206 | 7,193 | 0.04% | 766 | 9.4 | City |
| Lake Mills | 8 | 6,725 | 6,231 | 1.86% | 1,610 | 4.2 | City |
| Edgerton | 9 | 6,007 | 5,943 | 0.27% | 1,444 | 4.2 | City |
| Milton | 10 | 5,635 | 5,725 | -0.41% | 1,213 | 4.6 | City |
| Summit | 11 | 5,441 | 4,824 | 2.91% | 263 | 20.7 | Village |
| Okauchee Lake | 12 | 4,735 | 4,373 | 0.49% | 1,268 | 3.7 | CDP |
| Marshall | 13 | 3,816 | 3,792 | 0.16% | 1,781 | 2.1 | Village |
| Waterloo | 14 | 3,650 | 3,492 | 1.08% | 962 | 3.8 | City |
| Johnson Creek | 15 | 3,477 | 3,331 | 1.05% | 1,148 | 3.0 | Village |
| Dousman | 16 | 2,414 | 2,429 | -0.17% | 810 | 3.0 | Village |
| Eagle | 17 | 2,168 | 2,078 | 1.03% | 1,559 | 1.4 | Village |
| Ixonia | 18 | 2,137 | 1,856 | 1.71% | 587 | 3.6 | CDP |
| Lake Ripley | 19 | 2,016 | 1,927 | 0.85% | 604 | 3.3 | CDP |
| Palmyra | 20 | 1,681 | 1,729 | -0.71% | 734 | 2.3 | Village |
| Cambridge | 21 | 1,677 | 1,640 | 0.54% | 1,139 | 1.5 | Village |
| Ashippun | 22 | 1,059 | 1,027 | 5.16% | 1,030 | 1.0 | CDP |
| Lake Koshkonong | 23 | 960 | 958 | -1.84% | 68 | 14.1 | CDP |
| Sullivan | 24 | 639 | 651 | -0.47% | 564 | 1.1 | Village |
| Oconomowoc Lake | 25 | 588 | 572 | 0.69% | 306 | 1.9 | Village |
| Rome | 26 | 564 | 647 | -1.57% | 152 | 3.7 | CDP |
| Hebron | 27 | 357 | 317 | 2.59% | 145 | 2.5 | CDP |
| Lowell | 28 | 301 | 309 | -0.66% | 304 | 1.0 | Village |
| Lake Lorraine | 29 | 284 | 259 | -1.04% | 254 | 1.1 | CDP |
| Lac La Belle | 30 | 283 | 278 | 0.36% | 256 | 1.1 | Village |
| Rockdale | 31 | 202 | 210 | -0.98% | 719 | 0.3 | Village |
| Helenville | 32 | 165 | 245 | -3.51% | 298 | 0.6 | CDP |
| Lebanon | 33 | 122 | 98 | -4.69% | 277 | 0.4 | CDP |
| Fulton | 34 | 43 | 61 | 7.5% | 276 | 0.2 | CDP |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Janesville is the largest city in Jefferson County.
Fulton is the smallest city in Jefferson County.
There are 34 cities in Jefferson County, Wisconsin.