| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Salem | 1 | 1,360 | 1,330 | 0.22% | 1,088 | 1 | City |
| Canistota | 2 | 670 | 629 | 0.9% | 1,194 | 1 | City |
| Bridgewater | 3 | 518 | 509 | 0.19% | 460 | 1 | City |
| Montrose | 4 | 477 | 464 | 0.21% | 1,133 | 0 | City |
| Spencer | 5 | 140 | 136 | 0.72% | 522 | 0 | City |
Salem is the largest city in McCook County, with a population of 1,360.
Spencer is the smallest city in McCook County, with a population of 140.
There are 5 cities in McCook County, South Dakota.