4 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| White River | 1 | 506 | 538 | -1.17% | 971 | 0.52 | City |
| Horse Creek | 2 | 259 | 175 | 7.03% | 273 | 0.95 | CDP |
| Norris | 3 | 156 | 148 | 0% | 188 | 0.83 | CDP |
| Wood | 4 | 40 | 42 | 0% | 163 | 0.25 | Town |
White River is the largest city in Mellette County, with a population of 506.
Wood is the smallest city in Mellette County.
There are 4 cities in Mellette County, South Dakota.