39 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mahnomen | 1 | 1,209 | 1,248 | -0.58% | 1,155 | 1 | City |
| Mahnomen | 2 | 1,209 | 1,242 | -0.58% | 1,155 | 1 | City |
| Pembina | 3 | 639 | 660 | -0.62% | 18 | 36 | Township |
| Pembina | 4 | 639 | 657 | -0.62% | 18 | 36 | Township |
| Naytahwaush | 5 | 446 | 476 | -1.76% | 154 | 3 | CDP |
| Island Lake | 6 | 308 | 315 | -0.65% | 9 | 34 | Township |
| Island Lake | 7 | 308 | 313 | -0.65% | 9 | 34 | Township |
| Little Elbow | 8 | 282 | 290 | -0.7% | 9 | 31 | Township |
| Little Elbow | 9 | 282 | 289 | -0.7% | 9 | 31 | Township |
| Oakland | 10 | 253 | 263 | -1.17% | 8 | 33 | Township |
| Oakland | 11 | 253 | 262 | -1.17% | 8 | 33 | Township |
| Mahnomen | 12 | 178 | 215 | -2.2% | 140 | 1 | CDP |
| Lake Grove | 13 | 176 | 181 | -0.56% | 5 | 35 | Township |
| Lake Grove | 14 | 176 | 180 | -0.56% | 5 | 35 | Township |
| La Garde | 15 | 164 | 168 | -0.61% | 5 | 34 | Township |
| La Garde | 16 | 164 | 167 | -0.61% | 5 | 34 | Township |
| Chief | 17 | 155 | 159 | -0.64% | 4 | 35 | Township |
| Chief | 18 | 155 | 158 | -0.64% | 4 | 35 | Township |
| Marsh Creek | 19 | 138 | 142 | -0.72% | 4 | 38 | Township |
| Marsh Creek | 20 | 138 | 141 | -0.72% | 4 | 38 | Township |
| Heier | 21 | 137 | 141 | -0.72% | 4 | 34 | Township |
| Heier | 22 | 137 | 140 | -0.72% | 4 | 34 | Township |
| Clover | 23 | 135 | 135 | 0% | 4 | 35 | Township |
| Clover | 24 | 135 | 134 | 0% | 4 | 35 | Township |
| Popple Grove | 25 | 115 | 119 | -0.86% | 3 | 37 | Township |
| Popple Grove | 26 | 115 | 118 | -0.86% | 3 | 37 | Township |
| Rosedale | 27 | 112 | 116 | -0.88% | 3 | 35 | Township |
| Rosedale | 28 | 112 | 115 | -0.88% | 3 | 35 | Township |
| Beaulieu | 29 | 99 | 101 | 0% | 3 | 34 | Township |
| Beaulieu | 30 | 99 | 100 | 0% | 3 | 34 | Township |
| Lengby | 31 | 88 | 91 | -1.12% | 358 | 0 | City |
| Lengby | 32 | 88 | 91 | -1.12% | 358 | 0 | City |
| Bejou | 33 | 82 | 85 | -1.2% | 286 | 0 | City |
| Bejou | 34 | 82 | 85 | -1.2% | 286 | 0 | City |
| Bejou | 35 | 67 | 70 | -1.47% | 2 | 37 | Township |
| Bejou | 36 | 67 | 70 | -1.47% | 2 | 37 | Township |
| Gregory | 37 | 58 | 59 | 0% | 2 | 35 | Township |
| Gregory | 38 | 58 | 59 | 0% | 2 | 35 | Township |
| Pine Bend | 39 | 35 | 51 | 6.06% | 28 | 1 | CDP |
Mahnomen is the largest city in Mahnomen County, with a population of 1,209.
Pine Bend is the smallest city in Mahnomen County, with a population of 35.
There are 39 cities in Mahnomen County, Minnesota.