11 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Madison | 1 | 6,045 | 6,159 | -0.38% | 1,310 | 4.62 | City |
| Lake Madison | 2 | 892 | 811 | 1.59% | 189 | 4.72 | CDP |
| Brant Lake South | 3 | 279 | 290 | 7.31% | 531 | 0.53 | CDP |
| Chester | 4 | 231 | 285 | -0.86% | 283 | 0.82 | CDP |
| Wentworth | 5 | 170 | 180 | -1.16% | 669 | 0.25 | Village |
| Ramona | 6 | 164 | 161 | 0.61% | 599 | 0.27 | Town |
| Golden View Colony | 7 | 134 | 102 | 7.2% | 139 | 0.96 | CDP |
| Winfred | 8 | 58 | 68 | 7.41% | 58 | 1 | CDP |
| Brant Lake | 9 | 55 | 57 | 0% | 355 | 0.15 | City |
| Nunda | 10 | 47 | 47 | 0% | 47 | 1.01 | Town |
| Shannon Colony | 11 | 34 | 27 | 6.25% | 135 | 0.25 | CDP |
Madison is the largest city in Lake County, with a population of 6,045.
Shannon Colony is the smallest city in Lake County.
There are 11 cities in Lake County, South Dakota.