9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Custer | 1 | 1,800 | 1,910 | -1.21% | 726 | 2.48 | City |
| Custer township | 2 | 377 | 372 | 0.27% | 12 | 31.31 | Township |
| Hermosa | 3 | 369 | 378 | -0.54% | 471 | 0.78 | Town |
| Hill View Heights | 4 | 229 | 65 | 1.78% | 105 | 2.19 | CDP |
| Buffalo Gap | 5 | 161 | 130 | 3.87% | 526 | 0.31 | Town |
| Angostura | 6 | 148 | 75 | 7.25% | 12 | 12.59 | CDP |
| Pringle | 7 | 110 | 112 | 0% | 455 | 0.24 | Town |
| Fairburn | 8 | 68 | 57 | 3.03% | 208 | 0.33 | Town |
| Custer township | 9 | 31 | 32 | 0% | 1 | 51.29 | Township |
Custer is the largest city in Custer County, with a population of 1,800.
Custer township is the smallest city in Custer County.
There are 9 cities in Custer County, South Dakota.