23 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Madison | 1 | 6,067 | 6,161 | -0.31% | 1,314 | 5 | City |
| Lake View | 2 | 816 | 800 | -0.12% | 29 | 28 | Township |
| Chester | 3 | 688 | 678 | -0.29% | 21 | 33 | Township |
| Herman | 4 | 678 | 672 | -0.44% | 21 | 33 | Township |
| Wentworth | 5 | 513 | 501 | 0% | 15 | 34 | Township |
| Franklin | 6 | 325 | 325 | -0.61% | 9 | 36 | Township |
| Farmington | 7 | 209 | 206 | 0% | 6 | 36 | Township |
| Le Roy | 8 | 196 | 193 | 0% | 5 | 36 | Township |
| Rutland | 9 | 189 | 189 | -1.05% | 5 | 36 | Township |
| Wentworth | 10 | 166 | 179 | -1.78% | 654 | 0 | Village |
| Ramona | 11 | 161 | 161 | 0% | 588 | 0 | Town |
| Madison | 12 | 129 | 127 | 0% | 4 | 36 | Township |
| Winfred | 13 | 128 | 124 | 0.79% | 4 | 36 | Township |
| Nunda | 14 | 111 | 111 | -0.89% | 3 | 35 | Township |
| Orland | 15 | 97 | 92 | 2.11% | 3 | 36 | Township |
| Badus | 16 | 92 | 91 | -1.08% | 3 | 35 | Township |
| Concord | 17 | 92 | 91 | -1.08% | 3 | 36 | Township |
| Chester | 18 | 87 | 87 | 0% | 3 | 28 | Township |
| Wayne | 19 | 85 | 82 | 1.19% | 2 | 36 | Township |
| Clarno | 20 | 69 | 71 | -1.43% | 2 | 36 | Township |
| Brant Lake | 21 | 55 | 57 | -1.79% | 355 | 0 | City |
| Nunda | 22 | 49 | 47 | 0% | 49 | 1 | Town |
| Madison | 23 | 15 | 15 | 0% | 0.00 | 35 | Township |
Madison is the largest city in Lake County, with a population of 6,067.
Madison is the smallest city in Lake County, with a population of 15.
There are 23 cities in Lake County, South Dakota.