Montana Population By County in 2020

Updated on January 29, 2024.

Based on the US Census Vintage data estimates, in 2020, the population of Montana was 1,087,075. Among all Montana counties, Yellowstone[object Promise] had the highest population (165,196), followed by Gallatin[object Promise] (119,585), and Missoula[object Promise] (118,337). Petroleum[object Promise] was the least populated county (500).

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 2020
Montana Population By County in 2020
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County Population % of State Population
Beaverhead 9381 0.86
Big Horn 13082 1.20
Blaine 7005 0.64
Broadwater 6857 0.63
Carbon 10510 0.97
Carter 1408 0.13
Cascade 84402 7.76
Chouteau 5895 0.54
Custer 11863 1.09
Daniels 1653 0.15
Dawson 8923 0.82
Deer Lodge 9420 0.87
Fallon 3028 0.28
Fergus 11469 1.06
Flathead 104862 9.65
Gallatin 119585 11.00
Garfield 1170 0.11
Glacier 13737 1.26
Golden Valley 821 0.08
Granite 3308 0.30
Hill 16263 1.50
Jefferson 12140 1.12
Judith Basin 2025 0.19
Lake 31246 2.87
Lewis and Clark 71168 6.55
Liberty 1956 0.18
Lincoln 19739 1.82
McCone 1730 0.16
Madison 8660 0.80
Meagher 1922 0.18
Mineral 4565 0.42
Missoula 118337 10.89
Musselshell 4745 0.44
Park 17224 1.58
Petroleum 500 0.05
Phillips 4208 0.39
Pondera 5879 0.54
Powder River 1693 0.16
Powell 6941 0.64
Prairie 1093 0.10
Ravalli 44409 4.09
Richland 11531 1.06
Roosevelt 10794 0.99
Rosebud 8305 0.76
Sanders 12463 1.15
Sheridan 3536 0.33
Silver Bow 35201 3.24
Stillwater 8997 0.83
Sweet Grass 3670 0.34
Teton 6256 0.57
Toole 4970 0.46
Treasure 758 0.07
Valley 7556 0.70
Wheatland 2083 0.19
Wibaux 937 0.09
Yellowstone 165196 15.20