25 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Milbank | 1 | 3,500 | 3,530 | -0.17% | 1,262 | 2.77 | City |
| Alban township | 2 | 627 | 606 | 1.29% | 12 | 54.08 | Township |
| Big Stone City | 3 | 410 | 410 | 0% | 342 | 1.20 | City |
| Melrose township | 4 | 392 | 382 | 1.29% | 8 | 47.72 | Township |
| Grant Center township | 5 | 386 | 376 | 1.05% | 11 | 35.81 | Township |
| Big Stone township | 6 | 325 | 315 | 1.25% | 10 | 31.64 | Township |
| Vernon township | 7 | 227 | 215 | 1.79% | 4 | 54.69 | Township |
| Blooming Valley township | 8 | 180 | 176 | 0.56% | 5 | 36.12 | Township |
| Osceola township | 9 | 164 | 157 | 1.86% | 4 | 42.79 | Township |
| Adams township | 10 | 160 | 150 | 1.91% | 3 | 54.51 | Township |
| Kilborn township | 11 | 151 | 147 | 0.67% | 4 | 35.79 | Township |
| McIntosh | 12 | 108 | 113 | -0.92% | 148 | 0.73 | City |
| Stockholm | 13 | 107 | 104 | 0.94% | 247 | 0.43 | Town |
| Stockholm township | 14 | 105 | 94 | 3.96% | 3 | 34.97 | Township |
| Mazeppa township | 15 | 101 | 94 | 3.06% | 2 | 51.77 | Township |
| Revillo | 16 | 98 | 98 | 0% | 587 | 0.17 | Town |
| Twin Brooks township | 17 | 92 | 91 | 0% | 3 | 36.37 | Township |
| Farmington township | 18 | 80 | 72 | 3.9% | 4 | 21.83 | Township |
| Georgia township | 19 | 80 | 79 | 0% | 2 | 35.15 | Township |
| La Bolt | 20 | 69 | 68 | 0% | 290 | 0.24 | Town |
| Strandburg | 21 | 67 | 66 | 0% | 893 | 0.07 | Town |
| Troy township | 22 | 55 | 56 | 0% | 2 | 34.71 | Township |
| Lura township | 23 | 49 | 50 | 0% | 2 | 31.76 | Township |
| Twin Brooks | 24 | 44 | 46 | 0% | 108 | 0.41 | Town |
| Marvin | 25 | 20 | 20 | 0% | 37 | 0.55 | Town |
Milbank is the largest city in Grant County, with a population of 3,500.
Marvin is the smallest city in Grant County.
There are 25 cities in Grant County, South Dakota.