25 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 |
| Alban | 2 | 627 | 611 | 0.64% | 12 | 54 | Township |
| Big Stone City | 3 | 414 | 410 | 0.24% | 346 | 1 | City |
| Melrose | 4 | 393 | 378 | 1.29% | 8 | 48 | Township |
| Grant Center | 5 | 385 | 373 | 0.79% | 11 | 36 | Township |
| Big Stone | 6 | 325 | 316 | 0.62% | 10 | 32 | Township |
| Vernon | 7 | 220 | 216 | 0% | 4 | 55 | Township |
| Blooming Valley | 8 | 178 | 176 | 0% | 5 | 36 | Township |
| Adams | 9 | 162 | 152 | 1.25% | 3 | 55 | Township |
| Osceola | 10 | 161 | 156 | 0.63% | 4 | 43 | Township |
| Kilborn | 11 | 150 | 148 | 0% | 4 | 36 | Township |
| Stockholm | 12 | 108 | 102 | 0.93% | 249 | 0 | Town |
| McIntosh | 13 | 105 | 113 | -0.94% | 144 | 1 | City |
| Revillo | 14 | 98 | 98 | 0% | 587 | 0 | Town |
| Stockholm | 15 | 97 | 94 | 0% | 3 | 35 | Township |
| Mazeppa | 16 | 96 | 94 | 0% | 2 | 52 | Township |
| Georgia | 17 | 92 | 85 | 2.22% | 3 | 35 | Township |
| Twin Brooks | 18 | 90 | 91 | -1.1% | 2 | 36 | Township |
| Farmington | 19 | 75 | 73 | 0% | 3 | 22 | Township |
| Strandburg | 20 | 66 | 65 | 0% | 880 | 0 | Town |
| Troy | 21 | 63 | 55 | 5% | 2 | 35 | Township |
| La Bolt | 22 | 62 | 61 | 0% | 261 | 0 | Town |
| Lura | 23 | 57 | 51 | 3.64% | 2 | 32 | Township |
| Twin Brooks | 24 | 47 | 46 | 0% | 116 | 0 | Town |
| Marvin | 25 | 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 25 cities in Grant County, South Dakota.