20 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Salem | 1 | 1,308 | 1,328 | -0.23% | 1,046 | 1 | City |
| Canistota | 2 | 649 | 630 | 0.46% | 1,157 | 1 | City |
| Bridgewater | 3 | 503 | 509 | -0.2% | 447 | 1 | City |
| Montrose | 4 | 458 | 466 | -0.22% | 1,088 | 0 | City |
| Spring Valley | 5 | 384 | 368 | 0% | 11 | 36 | Township |
| Greenland | 6 | 328 | 321 | -0.91% | 9 | 35 | Township |
| Salem | 7 | 277 | 268 | 0% | 8 | 35 | Township |
| Montrose | 8 | 218 | 212 | -0.46% | 6 | 35 | Township |
| Richland | 9 | 166 | 163 | -1.19% | 5 | 36 | Township |
| Grant | 10 | 153 | 150 | -1.29% | 4 | 36 | Township |
| Canistota | 11 | 151 | 151 | -1.95% | 4 | 36 | Township |
| Sun Prairie | 12 | 139 | 131 | 0.72% | 4 | 36 | Township |
| Spencer | 13 | 136 | 136 | 0% | 507 | 0 | City |
| Salem | 14 | 134 | 131 | -0.74% | 4 | 36 | Township |
| Brookfield | 15 | 133 | 128 | 0% | 4 | 36 | Township |
| Union | 16 | 127 | 122 | 0% | 4 | 36 | Township |
| Bridgewater | 17 | 120 | 117 | -0.83% | 3 | 35 | Township |
| Ramsey | 18 | 98 | 97 | -1.01% | 3 | 36 | Township |
| Benton | 19 | 96 | 95 | -1.03% | 3 | 35 | Township |
| Pearl | 20 | 60 | 55 | 1.69% | 2 | 36 | Township |
Salem is the largest city in McCook County, with a population of 1,308.
Pearl is the smallest city in McCook County, with a population of 60.
There are 20 cities in McCook County, South Dakota.