Montana Population By County in 2021

Updated on January 29, 2024.

Based on the US Census Vintage data estimates, in 2021, the population of Montana was 1,106,227. Among all Montana counties, Yellowstone[object Promise] had the highest population (167,397), followed by Gallatin[object Promise] (123,051), and Missoula[object Promise] (119,806). Petroleum[object Promise] was the least populated county (522).

Hover over or click on the counties in the map below to see the populations. The data can also be found in a table below. You can use the table to sort, filter, and explore the data further.

You can see similar information for other states and by state for the United States.

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Montana Population By County in 2021
Montana Population By County in 2021
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County Population % of State Population
Beaverhead 9532 0.86
Big Horn 12932 1.17
Blaine 6982 0.63
Broadwater 7323 0.66
Carbon 10862 0.98
Carter 1410 0.13
Cascade 84498 7.64
Chouteau 5916 0.54
Custer 11971 1.08
Daniels 1669 0.15
Dawson 8866 0.80
Deer Lodge 9506 0.86
Fallon 2984 0.27
Fergus 11609 1.05
Flathead 108725 9.83
Gallatin 123051 11.12
Garfield 1210 0.11
Glacier 13743 1.24
Golden Valley 818 0.07
Granite 3355 0.30
Hill 16175 1.46
Jefferson 12472 1.13
Judith Basin 2052 0.19
Lake 32075 2.90
Lewis and Clark 72503 6.55
Liberty 1934 0.18
Lincoln 20571 1.86
McCone 1711 0.16
Madison 8944 0.81
Meagher 1960 0.18
Mineral 4868 0.44
Missoula 119806 10.83
Musselshell 4912 0.44
Park 17531 1.59
Petroleum 522 0.05
Phillips 4216 0.38
Pondera 6018 0.54
Powder River 1707 0.15
Powell 7012 0.63
Prairie 1101 0.10
Ravalli 46125 4.17
Richland 11342 1.02
Roosevelt 10808 0.98
Rosebud 8077 0.73
Sanders 12975 1.17
Sheridan 3569 0.32
Silver Bow 35554 3.21
Stillwater 9026 0.82
Sweet Grass 3705 0.34
Teton 6282 0.57
Toole 5010 0.45
Treasure 769 0.07
Valley 7556 0.68
Wheatland 2045 0.19
Wibaux 935 0.09
Yellowstone 167397 15.13