Montana 2015 Population By County
Updated on December 2, 2021.

According to the US Census Bureau population estimates, there were 1,031,495 people living in Montana in 2015. Yellowstone County was the most populated county with 156,658 residents, followed by Missoula County with 114,281 residents, and Gallatin County with 101,043 residents. Petroleum County with a population of 475 was the least populated county in Montana in 2015.

Use the map below to interactively explore the population of each county in Montana in 2015. The data can also be explored further by sorting and filtering with the table below.

Montana 2015 Population By County
See also Population estimate for other years:
Table of Montana 2015 Population By County
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County Population % of State Population
Beaverhead 9,303 0.90
Big Horn 13,310 1.29
Blaine 6,683 0.65
Broadwater 5,717 0.55
Carbon 10,404 1.01
Carter 1,147 0.11
Cascade 81,959 7.95
Chouteau 5,777 0.56
Custer 12,098 1.17
Daniels 1,751 0.17
Dawson 9,591 0.93
Deer Lodge 9,115 0.88
Fallon 3,172 0.31
Fergus 11,315 1.10
Flathead 95,940 9.30
Gallatin 101,043 9.80
Garfield 1,283 0.12
Glacier 13,647 1.32
Golden Valley 818 0.08
Granite 3,160 0.31
Hill 16,435 1.59
Jefferson 11,576 1.12
Judith Basin 1,932 0.19
Lake 29,482 2.86
Lewis and Clark 66,308 6.43
Liberty 2,395 0.23
Lincoln 19,085 1.85
McCone 1,698 0.17
Madison 8,033 0.78
Meagher 1,822 0.18
Mineral 4,194 0.41
Missoula 114,281 11.08
Musselshell 4,631 0.45
Park 16,013 1.55
Petroleum 475 0.05
Phillips 4,150 0.40
Pondera 6,100 0.59
Powder River 1,768 0.17
Powell 6,793 0.66
Prairie 1,140 0.11
Ravalli 41,199 3.99
Richland 11,931 1.16
Roosevelt 11,416 1.11
Rosebud 9,355 0.91
Sanders 11,298 1.10
Sheridan 3,673 0.36
Silver Bow 34,746 3.37
Stillwater 9,419 0.91
Sweet Grass 3,618 0.35
Teton 6,064 0.59
Toole 5,083 0.49
Treasure 680 0.07
Valley 7,630 0.74
Wheatland 2,110 0.21
Wibaux 1,071 0.10
Yellowstone 156,658 15.19