14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fort Belknap Agency | 1 | 1,518 | 1,520 | 1% | 33 | 46 | CDP |
| Chinook | 2 | 1,158 | 1,178 | -0.34% | 2,214 | 1 | City |
| Hays | 3 | 1,158 | 947 | 1.85% | 43 | 27 | CDP |
| Havre North | 4 | 881 | 593 | 1.26% | 263 | 3 | CDP |
| Harlem | 5 | 754 | 768 | -0.4% | 1,804 | 0 | City |
| Beaver Creek | 6 | 410 | 424 | 2.5% | 89 | 5 | CDP |
| Lodge Pole | 7 | 233 | 344 | -0.85% | 17 | 13 | CDP |
| Saddle Butte | 8 | 193 | 101 | 2.12% | 77 | 3 | CDP |
| West Havre | 9 | 101 | 130 | -12.17% | 53 | 2 | CDP |
| Turner | 10 | 86 | 95 | 7.5% | 193 | 0 | CDP |
| North Harlem Colony | 11 | 71 | 26 | 7.58% | 242 | 0 | CDP |
| Zurich | 12 | 50 | 65 | 6.38% | 93 | 1 | CDP |
| Hogeland | 13 | 27 | 24 | 3.85% | 53 | 1 | CDP |
| Herron | 14 | 6 | 188 | -53.85% | 1 | 5 | CDP |
Fort Belknap Agency is the largest city in Blaine County, with a population of 1,518.
Herron is the smallest city in Blaine County, with a population of 6.
There are 14 cities in Blaine County, Montana.