9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Belle Fourche | 1 | 5,906 | 5,648 | 0.87% | 667 | 9 | City |
| North Spearfish | 2 | 1,684 | 2,251 | -2.04% | 393 | 4 | CDP |
| Mountain Plains | 3 | 601 | 394 | 7.13% | 377 | 2 | CDP |
| Newell | 4 | 586 | 578 | 0.17% | 579 | 1 | City |
| Nisland | 5 | 212 | 207 | 0.47% | 788 | 0 | Town |
| Crook City | 6 | 159 | 130 | 7.43% | 175 | 1 | CDP |
| Vale | 7 | 123 | 114 | 0.82% | 318 | 0 | Township |
| Vale | 8 | 82 | 114 | -4.65% | 55 | 1 | CDP |
| Union | 9 | 21 | 19 | 0% | 0.00 | 141 | Township |
Belle Fourche is the largest city in Butte County, with a population of 5,906.
Union is the smallest city in Butte County, with a population of 21.
There are 9 cities in Butte County, South Dakota.