Montana Citizen Population By County in 2018 (ACS-5Yrs)

Updated on March 28, 2026.

Based on the US Census Bureau's special tabulation from the ACS 5-year estimates, in 2018, the citizen population for Montana was 1,031,015 and represented 98.97% of the total Montana population.

Among all Montana counties, Yellowstone had the highest citizen population (156.40K), followed by Missoula (114.24K), and Gallatin (102.66K).

In terms of percentages, Blaine had the highest percentage of its population being citizens (100.00%), followed by Carter (100.00%), and Garfield (100.00%).

The chart and table below shows the citizen population of each county and the percentage of each county's population that were citizens.

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

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Montana Citizen Population By County in 2018
Montana Citizen Population By County in 2018
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County Citizen Population % of County Population
Yellowstone 156395 99.10
Missoula 114240 98.50
Gallatin 102660 98.02
Flathead 97420 99.33
Cascade 81125 99.24
Lewis and Clark 66675 99.40
Ravalli 41615 99.32
Silver Bow 34300 98.52
Lake 29480 99.01
Lincoln 19080 98.55
Hill 16325 99.30
Park 16090 99.05
Glacier 13550 98.91
Big Horn 13255 99.10
Custer 11770 99.37
Jefferson 11745 99.70
Sanders 11425 99.18
Richland 11205 98.64
Fergus 11190 99.25
Roosevelt 11150 99.29
Carbon 10515 99.72
Stillwater 9335 99.20
Beaverhead 9180 97.71
Rosebud 9170 99.14
Dawson 9115 99.18
Deer Lodge 9030 99.23
Madison 7915 96.29
Valley 7470 99.20
Powell 6850 99.85
Blaine 6725 100.00
Teton 6050 99.51
Pondera 6005 99.34
Broadwater 5805 99.49
Chouteau 5750 99.31
Toole 4960 99.70
Musselshell 4795 99.79
Mineral 4210 100.00
Phillips 4100 99.39
Sweet Grass 3635 99.45
Sheridan 3535 98.88
Granite 3245 99.24
Fallon 2800 98.59
Liberty 2280 100.00
Wheatland 2110 98.14
Meagher 1950 98.99
Judith Basin 1945 99.74
Daniels 1745 99.43
McCone 1620 99.39
Powder River 1600 98.77
Prairie 1330 99.25
Carter 1320 100.00
Wibaux 1155 98.30
Garfield 1140 100.00
Treasure 775 100.00
Golden Valley 725 100.00
Petroleum 430 100.00