3 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Eagle Butte | 1 | 1,275 | 1,249 | 0.39% | 936 | 1 | City |
| Timber Lake | 2 | 543 | 512 | 1.12% | 889 | 1 | City |
| Isabel | 3 | 157 | 146 | 1.29% | 186 | 1 | Town |
Eagle Butte is the largest city in Dewey County, with a population of 1,275.
Isabel is the smallest city in Dewey County, with a population of 157.
There are 3 cities in Dewey County, South Dakota.