27 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fairmont | 1 | 10,103 | 10,445 | -0.67% | 674 | 15 | City |
| Truman | 2 | 1,047 | 1,089 | -0.76% | 953 | 1 | City |
| Sherburn | 3 | 1,044 | 1,058 | -0.29% | 1,136 | 1 | City |
| Welcome | 4 | 690 | 709 | -0.58% | 474 | 1 | City |
| Trimont | 5 | 682 | 709 | -0.73% | 868 | 1 | City |
| Rutland | 6 | 367 | 371 | 0% | 10 | 36 | Township |
| Fairmont | 7 | 315 | 318 | 0% | 15 | 21 | Township |
| Manyaska | 8 | 313 | 310 | 0.64% | 9 | 34 | Township |
| Ceylon | 9 | 293 | 305 | -0.68% | 567 | 1 | City |
| Granada | 10 | 277 | 289 | -0.72% | 485 | 1 | City |
| East Chain | 11 | 275 | 277 | 0% | 8 | 35 | Township |
| Fraser | 12 | 269 | 271 | 0% | 7 | 36 | Township |
| Fox Lake | 13 | 257 | 259 | 0% | 8 | 34 | Township |
| Westford | 14 | 253 | 255 | 0% | 7 | 36 | Township |
| Rolling Green | 15 | 246 | 248 | 0% | 7 | 34 | Township |
| Jay | 16 | 235 | 233 | 0.86% | 6 | 36 | Township |
| Tenhassen | 17 | 228 | 232 | -0.44% | 7 | 33 | Township |
| Pleasant Prairie | 18 | 223 | 225 | 0% | 6 | 36 | Township |
| Center Creek | 19 | 216 | 214 | 0.93% | 6 | 35 | Township |
| Northrop | 20 | 213 | 223 | -0.93% | 1,626 | 0 | City |
| Galena | 21 | 210 | 208 | 0.96% | 6 | 35 | Township |
| Nashville | 22 | 204 | 206 | 0% | 6 | 36 | Township |
| Lake Belt | 23 | 185 | 187 | 0% | 5 | 35 | Township |
| Elm Creek | 24 | 165 | 162 | 1.23% | 5 | 35 | Township |
| Lake Fremont | 25 | 157 | 154 | 1.29% | 4 | 36 | Township |
| Dunnell | 26 | 124 | 131 | -0.8% | 810 | 0 | City |
| Ormsby | 27 | 123 | 120 | 0.82% | 348 | 0 | City |
Fairmont is the largest city in Martin County, with a population of 10,103.
Ormsby is the smallest city in Martin County, with a population of 123.
There are 27 cities in Martin County, Minnesota.