Montana Counties by Population (2026)
2026 Pop.
20K
40K
60K
80K
100K
120K
140K
160K
Top 5 Most Populous Counties
173,836
129,982
124,555
116,491
85,390
| County | 2026 Pop. ↓ | Area (mi²) | Density (/mi²) | Change (2020) |
|---|---|---|---|---|
| Yellowstone County | 173,836 | 2.6K | 66 | 5.22% |
| Gallatin County | 129,982 | 2.6K | 50 | 8.69% |
| Missoula County | 124,555 | 2.6K | 48 | 5.25% |
| Flathead County | 116,491 | 5.1K | 23 | 11.08% |
| Cascade County | 85,390 | 2.7K | 32 | 1.16% |
| Lewis and Clark County | 75,570 | 3.5K | 22 | 6.17% |
| Ravalli County | 49,127 | 2.4K | 21 | 10.62% |
| Silver Bow County | 36,145 | 718 | 50 | 2.66% |
| Lake County | 33,401 | 1.5K | 22 | 6.9% |
| Lincoln County | 22,509 | 3.6K | 6.2 | 14.04% |
| Park County | 18,255 | 2.8K | 6.5 | 5.96% |
| Hill County | 16,219 | 2.9K | 5.6 | -0.18% |
| Sanders County | 14,232 | 2.8K | 5.2 | 14.28% |
| Jefferson County | 13,427 | 1.7K | 8.1 | 10.59% |
| Glacier County | 13,411 | 3K | 4.5 | -2.37% |
| Big Horn County | 12,657 | 5K | 2.5 | -3.23% |
| Custer County | 12,091 | 3.8K | 3.2 | 1.95% |
| Fergus County | 11,824 | 4.3K | 2.7 | 3.06% |
| Richland County | 11,683 | 2.1K | 5.6 | 1.35% |
| Carbon County | 11,428 | 2K | 5.6 | 8.72% |
| Madison County | 10,280 | 3.6K | 2.9 | 18.75% |
| Roosevelt County | 10,274 | 2.4K | 4.4 | -4.94% |
| Beaverhead County | 10,096 | 5.5K | 1.8 | 7.69% |
| Deer Lodge County | 9,652 | 737 | 13 | 2.41% |
| Stillwater County | 9,461 | 1.8K | 5.3 | 5.15% |
| Broadwater County | 8,697 | 1.2K | 7.3 | 26.78% |
| Dawson County | 8,645 | 2.4K | 3.6 | -3.09% |
| Rosebud County | 8,288 | 5K | 1.7 | -0.25% |
| Valley County | 7,385 | 4.9K | 1.5 | -2.37% |
| Powell County | 7,193 | 2.3K | 3.1 | 3.63% |
| Blaine County | 6,844 | 4.2K | 1.6 | -2.35% |
| Teton County | 6,553 | 2.3K | 2.9 | 4.81% |
| Pondera County | 6,079 | 1.6K | 3.7 | 3.33% |
| Chouteau County | 5,877 | 4K | 1.5 | -0.58% |
| Musselshell County | 5,712 | 1.9K | 3.1 | 20.3% |
| Toole County | 5,269 | 1.9K | 2.8 | 6.08% |
| Mineral County | 5,183 | 1.2K | 4.2 | 13.49% |
| Phillips County | 4,210 | 5.1K | 0.82 | 0.05% |
| Sweet Grass County | 3,706 | 1.9K | 2.0 | 0.87% |
| Granite County | 3,677 | 1.7K | 2.1 | 11.19% |
| Sheridan County | 3,394 | 1.7K | 2.0 | -4.12% |
| Fallon County | 2,958 | 1.6K | 1.8 | -2.34% |
| Judith Basin County | 2,209 | 1.9K | 1.2 | 9.09% |
| Meagher County | 2,179 | 2.4K | 0.91 | 13.37% |
| Wheatland County | 2,142 | 1.4K | 1.5 | 3.23% |
| Liberty County | 1,963 | 1.4K | 1.4 | 0.36% |
| Powder River County | 1,804 | 3.3K | 0.55 | 6.49% |
| McCone County | 1,725 | 2.6K | 0.65 | -0.35% |
| Daniels County | 1,581 | 1.4K | 1.1 | -4.18% |
| Carter County | 1,344 | 3.3K | 0.40 | -4.41% |
| Garfield County | 1,121 | 4.7K | 0.24 | -4.19% |
| Prairie County | 1,116 | 1.7K | 0.64 | 2.01% |
| Wibaux County | 858 | 890 | 0.96 | -8.33% |
| Golden Valley County | 844 | 1.2K | 0.72 | 2.68% |
| Treasure County | 721 | 978 | 0.74 | -4.88% |
| Petroleum County | 558 | 1.7K | 0.34 | 11.16% |
Sources
- US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
- US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
- American Community Survey (2009 - 2013)
- Census QuickFacts
- Historical Populations of States and Counties (1790 - 1990)