| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Milbank | 1 | 3,515 | 3,531 | 0.09% | 1,267 | 3 | City |
| Big Stone City | 2 | 406 | 410 | 0% | 339 | 1 | City |
| McIntosh | 3 | 107 | 114 | -1.83% | 147 | 1 | City |
| Stockholm | 4 | 103 | 100 | 0.98% | 238 | 0 | Town |
| Revillo | 5 | 96 | 98 | 0% | 575 | 0 | Town |
| Strandburg | 6 | 65 | 65 | 0% | 867 | 0 | Town |
| La Bolt | 7 | 62 | 62 | 0% | 261 | 0 | Town |
| Twin Brooks | 8 | 47 | 47 | 0% | 116 | 0 | Town |
| Marvin | 9 | 19 | 18 | 0% | 35 | 1 | Town |
Milbank is the largest city in Grant County, with a population of 3,515.
Marvin is the smallest city in Grant County, with a population of 19.
There are 9 cities in Grant County, South Dakota.