Montana Population By County in 2021

Updated on August 1, 2024.

Based on the US Census Vintage data estimates, in 2021, the population of Montana was 1,106,366. Among all Montana counties, Yellowstone had the highest population (167,438), followed by Gallatin (123,098), and Missoula (119,841). Petroleum was the least populated county (518).

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 9553 0.86
Big Horn 12893 1.17
Blaine 7003 0.63
Broadwater 7323 0.66
Carbon 10889 0.98
Carter 1413 0.13
Cascade 84551 7.64
Chouteau 5921 0.54
Custer 11961 1.08
Daniels 1671 0.15
Dawson 8858 0.80
Deer Lodge 9518 0.86
Fallon 3011 0.27
Fergus 11622 1.05
Flathead 108769 9.83
Gallatin 123098 11.13
Garfield 1208 0.11
Glacier 13724 1.24
Golden Valley 815 0.07
Granite 3360 0.30
Hill 16220 1.47
Jefferson 12468 1.13
Judith Basin 2038 0.18
Lake 32090 2.90
Lewis and Clark 72507 6.55
Liberty 1933 0.18
Lincoln 20582 1.86
McCone 1709 0.15
Madison 8953 0.81
Meagher 1958 0.18
Mineral 4859 0.44
Missoula 119841 10.83
Musselshell 4908 0.44
Park 17515 1.58
Petroleum 518 0.05
Phillips 4210 0.38
Pondera 6018 0.54
Powder River 1710 0.16
Powell 7025 0.64
Prairie 1097 0.10
Ravalli 46084 4.17
Richland 11329 1.02
Roosevelt 10788 0.98
Rosebud 8086 0.73
Sanders 12944 1.17
Sheridan 3576 0.32
Silver Bow 35502 3.21
Stillwater 9024 0.82
Sweet Grass 3702 0.34
Teton 6275 0.57
Toole 4992 0.45
Treasure 768 0.07
Valley 7560 0.68
Wheatland 2042 0.19
Wibaux 936 0.09
Yellowstone 167438 15.13