15 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Gregory | 1 | 1,289 | 1,231 | 0.78% | 749 | 2 | City |
| Burke | 2 | 595 | 580 | 0.51% | 1,064 | 1 | City |
| Bonesteel | 3 | 262 | 253 | 0.77% | 740 | 0 | City |
| Pleasant Valley | 4 | 174 | 163 | 1.75% | 5 | 36 | Township |
| Herrick | 5 | 153 | 149 | 0% | 4 | 43 | Township |
| Fairfax | 6 | 105 | 99 | 0.96% | 347 | 0 | Town |
| Jones | 7 | 85 | 76 | 3.66% | 2 | 36 | Township |
| Dallas | 8 | 85 | 87 | 0% | 168 | 1 | Town |
| Dixon | 9 | 84 | 79 | 1.2% | 1 | 65 | Township |
| Star Valley | 10 | 83 | 78 | 1.22% | 2 | 48 | Township |
| Edens | 11 | 78 | 73 | 1.3% | 2 | 36 | Township |
| Herrick | 12 | 78 | 75 | 1.3% | 151 | 1 | Town |
| Fairfax | 13 | 66 | 60 | 3.13% | 2 | 32 | Township |
| Schriever | 14 | 43 | 40 | 2.38% | 2 | 24 | Township |
| Landing Creek | 15 | 20 | 20 | 0% | 0.00 | 62 | Township |
Gregory is the largest city in Gregory County, with a population of 1,289.
Landing Creek is the smallest city in Gregory County, with a population of 20.
There are 15 cities in Gregory County, South Dakota.