| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Madison | 1 | 6,050 | 6,160 | -0.25% | 1,311 | 5 | City |
| Wentworth | 2 | 170 | 181 | -1.16% | 669 | 0 | Village |
| Ramona | 3 | 163 | 161 | 0% | 595 | 0 | Town |
| Brant Lake | 4 | 55 | 58 | -1.79% | 355 | 0 | City |
| Nunda | 5 | 46 | 45 | 0% | 46 | 1 | Town |
Madison is the largest city in Lake County, with a population of 6,050.
Nunda is the smallest city in Lake County, with a population of 46.
There are 5 cities in Lake County, South Dakota.