9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Milbank | 1 | 3,550 | 3,534 | 0.08% | 1,280 | 3 | City |
| Big Stone City | 2 | 414 | 410 | 0.24% | 346 | 1 | City |
| Stockholm | 3 | 108 | 102 | 0.93% | 249 | 0 | Town |
| McIntosh | 4 | 105 | 113 | -0.94% | 144 | 1 | City |
| Revillo | 5 | 98 | 98 | 0% | 587 | 0 | Town |
| Strandburg | 6 | 66 | 65 | 0% | 880 | 0 | Town |
| La Bolt | 7 | 62 | 61 | 0% | 261 | 0 | Town |
| Twin Brooks | 8 | 47 | 46 | 0% | 116 | 0 | Town |
| Marvin | 9 | 19 | 19 | 0% | 35 | 1 | Town |
Milbank is the largest city in Grant County, with a population of 3,550.
Marvin is the smallest city in Grant County, with a population of 19.
There are 9 cities in Grant County, South Dakota.