Montana Population By County in 2015

Updated on January 27, 2024.

Based on the US Census Vintage data estimates, in 2015, the population of Montana was 1,031,495. Among all Montana counties, Yellowstone had the highest population (156,658), followed by Missoula (114,281), and Gallatin (101,043). Petroleum was the least populated county (475).

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 2015
Montana Population By County in 2015
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County Population % of State Population
Beaverhead 9303 0.90
Big Horn 13310 1.29
Blaine 6683 0.65
Broadwater 5717 0.55
Carbon 10404 1.01
Carter 1147 0.11
Cascade 81959 7.95
Chouteau 5777 0.56
Custer 12098 1.17
Daniels 1751 0.17
Dawson 9591 0.93
Deer Lodge 9115 0.88
Fallon 3172 0.31
Fergus 11315 1.10
Flathead 95940 9.30
Gallatin 101043 9.80
Garfield 1283 0.12
Glacier 13647 1.32
Golden Valley 818 0.08
Granite 3160 0.31
Hill 16435 1.59
Jefferson 11576 1.12
Judith Basin 1932 0.19
Lake 29482 2.86
Lewis and Clark 66308 6.43
Liberty 2395 0.23
Lincoln 19085 1.85
McCone 1698 0.17
Madison 8033 0.78
Meagher 1822 0.18
Mineral 4194 0.41
Missoula 114281 11.08
Musselshell 4631 0.45
Park 16013 1.55
Petroleum 475 0.05
Phillips 4150 0.40
Pondera 6100 0.59
Powder River 1768 0.17
Powell 6793 0.66
Prairie 1140 0.11
Ravalli 41199 3.99
Richland 11931 1.16
Roosevelt 11416 1.11
Rosebud 9355 0.91
Sanders 11298 1.10
Sheridan 3673 0.36
Silver Bow 34746 3.37
Stillwater 9419 0.91
Sweet Grass 3618 0.35
Teton 6064 0.59
Toole 5083 0.49
Treasure 680 0.07
Valley 7630 0.74
Wheatland 2110 0.21
Wibaux 1071 0.10
Yellowstone 156658 15.19