| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| DeForest | 1 | 13,441 | 10,822 | 2.65% | 1,414 | 10 | Village |
| Portage | 2 | 9,799 | 10,585 | -1.58% | 1,100 | 9 | City |
| Columbus | 3 | 5,372 | 5,535 | -0.52% | 1,184 | 5 | City |
| Prairie du Sac | 4 | 4,302 | 4,421 | -0.32% | 2,159 | 2 | Village |
| Lodi | 5 | 3,189 | 3,194 | -0.03% | 1,841 | 2 | City |
| Wisconsin Dells | 6 | 3,184 | 3,012 | 1.11% | 406 | 8 | City |
| Poynette | 7 | 2,981 | 2,600 | 1.95% | 1,160 | 3 | Village |
| Pardeeville | 8 | 2,293 | 2,074 | 2% | 1,191 | 2 | Village |
| Fall River | 9 | 1,851 | 1,855 | -0.11% | 980 | 2 | Village |
| Randolph | 10 | 1,763 | 1,795 | -0.45% | 1,421 | 1 | Village |
| West Baraboo | 11 | 1,562 | 1,630 | -0.64% | 1,239 | 1 | Village |
| Rio | 12 | 1,123 | 1,128 | 0% | 896 | 1 | Village |
| Arlington | 13 | 855 | 849 | -0.58% | 824 | 1 | Village |
| Cambria | 14 | 763 | 772 | -0.26% | 777 | 1 | Village |
| Wyocena | 15 | 725 | 760 | -1.09% | 506 | 1 | Village |
| Friesland | 16 | 316 | 317 | -0.32% | 313 | 1 | Village |
| Doylestown | 17 | 270 | 278 | -0.74% | 70 | 4 | Village |
DeForest is the largest city in Columbia County, with a population of 13,441.
Doylestown is the smallest city in Columbia County, with a population of 270.
There are 17 cities in Columbia County, Wisconsin.