5 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Lewistown | 1 | 6,320 | 5,971 | 0.93% | 1,105 | 6 | City |
| Denton | 2 | 215 | 206 | 0.94% | 302 | 1 | Town |
| Moore | 3 | 205 | 193 | 0.99% | 702 | 0 | Town |
| Winifred | 4 | 178 | 171 | 0.56% | 340 | 1 | Town |
| Grass Range | 5 | 117 | 110 | 0.86% | 836 | 0 | Town |
Lewistown is the largest city in Fergus County, with a population of 6,320.
Grass Range is the smallest city in Fergus County, with a population of 117.
There are 5 cities in Fergus County, Montana.