10 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fairmont | 1 | 10,042 | 10,444 | -0.66% | 670 | 15 | City |
| Truman | 2 | 1,055 | 1,097 | -0.66% | 960 | 1 | City |
| Sherburn | 3 | 1,044 | 1,061 | -0.29% | 1,136 | 1 | City |
| Welcome | 4 | 688 | 709 | -0.43% | 473 | 1 | City |
| Trimont | 5 | 678 | 710 | -0.73% | 863 | 1 | City |
| Ceylon | 6 | 290 | 305 | -0.68% | 561 | 1 | City |
| Granada | 7 | 277 | 289 | -0.72% | 485 | 1 | City |
| Northrop | 8 | 213 | 224 | -0.93% | 1,626 | 0 | City |
| Dunnell | 9 | 124 | 132 | -0.8% | 810 | 0 | City |
| Ormsby | 10 | 124 | 121 | 0.81% | 351 | 0 | City |
Fairmont is the largest city in Martin County, with a population of 10,042.
Ormsby is the smallest city in Martin County, with a population of 124.
There are 10 cities in Martin County, Minnesota.