3 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Eagle Butte | 1 | 1,280 | 1,249 | 0.39% | 940 | 1 | City |
| Timber Lake | 2 | 549 | 512 | 1.1% | 899 | 1 | City |
| Isabel | 3 | 159 | 146 | 1.27% | 188 | 1 | Town |
Eagle Butte is the largest city in Dewey County, with a population of 1,280.
Isabel is the smallest city in Dewey County, with a population of 159.
There are 3 cities in Dewey County, South Dakota.