9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Belle Fourche | 1 | 6,031 | 5,635 | 1.33% | 681 | 8.85 | City |
| North Spearfish | 2 | 1,684 | 2,251 | -2.04% | 393 | 4.28 | CDP |
| Newell | 3 | 605 | 585 | 0.67% | 598 | 1.01 | City |
| Mountain Plains | 4 | 601 | 394 | 7.13% | 377 | 1.59 | CDP |
| Nisland | 5 | 217 | 207 | 0.93% | 807 | 0.27 | Town |
| Crook City | 6 | 159 | 130 | 7.43% | 175 | 0.91 | CDP |
| Vale township | 7 | 118 | 113 | -0.84% | 305 | 0.39 | Township |
| Vale | 8 | 82 | 114 | -4.65% | 55 | 1.49 | CDP |
| Union township | 9 | 22 | 20 | 0% | 0.00 | 141.20 | Township |
Belle Fourche is the largest city in Butte County, with a population of 6,031.
Union township is the smallest city in Butte County.
There are 9 cities in Butte County, South Dakota.