Data / Rankings / Population aged 18 to 64 / Counties in Montana

Counties in Montana by population aged 18 to 64

Gallatin County had the highest population aged 18 to 64 of 56 counties in 2024, at 67.3%. Prairie County had the lowest, at 41.8%. The median was 53% and the figure for Montana was 57.8%. Source: the U.S. Census Bureau.

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Highest67.3Gallatin County
Lowest41.8Prairie County
Median5356 counties
Montana57.8History

Map of counties, 2024

Beaverhead County: 57.1 %Big Horn County: 54.5 %Blaine County: 54.7 %Broadwater County: 55.4 %Carbon County: 52.5 %Carter County: 49.9 %Cascade County: 57.8 %Chouteau County: 53.3 %Custer County: 56.8 %Daniels County: 50.5 %Dawson County: 56 %Deer Lodge County: 56.6 %Fallon County: 52.8 %Fergus County: 51.5 %Flathead County: 55.8 %Gallatin County: 67.3 %Garfield County: 48.9 %Glacier County: 56.2 %Golden Valley County: 48 %Granite County: 54.9 %Hill County: 54.7 %Jefferson County: 53.7 %Judith Basin County: 50.3 %Lake County: 52.4 %Lewis and Clark County: 57.7 %Liberty County: 50.1 %Lincoln County: 50.4 %McCone County: 51.1 %Madison County: 54 %Meagher County: 51.5 %Mineral County: 53.3 %Missoula County: 62.8 %Musselshell County: 52.2 %Park County: 58.7 %Petroleum County: 48.9 %Phillips County: 51.5 %Pondera County: 52.5 %Powder River County: 48.7 %Powell County: 60.4 %Prairie County: 41.8 %Ravalli County: 51.8 %Richland County: 57.2 %Roosevelt County: 53.4 %Rosebud County: 53.5 %Sanders County: 49.1 %Sheridan County: 52.7 %Silver Bow County: 58.6 %Stillwater County: 51.9 %Sweet Grass County: 52.4 %Teton County: 51.5 %Toole County: 60.9 %Treasure County: 46 %Valley County: 52.7 %Wheatland County: 50.1 %Wibaux County: 53.5 %Yellowstone County: 58.2 %
  • Under 50
  • 50 to 52
  • 52 to 53
  • 53 to 55
  • 55 to 57
  • 57 and over
%, 2024. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2024

Gallatin County: 67.3 %Gallatin County67.3Missoula County: 62.8 %Missoula County62.8Toole County: 60.9 %Toole County60.9Powell County: 60.4 %Powell County60.4Park County: 58.7 %Park County58.7Silver Bow County: 58.6 %Silver Bow County58.6Yellowstone County: 58.2 %Yellowstone County58.2Cascade County: 57.8 %Cascade County57.8Lewis and Clark County: 57.7 %Lewis and Clark County57.7Richland County: 57.2 %Richland County57.2Beaverhead County: 57.1 %Beaverhead County57.1Custer County: 56.8 %Custer County56.8Deer Lodge County: 56.6 %Deer Lodge County56.6Glacier County: 56.2 %Glacier County56.2Dawson County: 56 %Dawson County56Flathead County: 55.8 %Flathead County55.8Broadwater County: 55.4 %Broadwater County55.4Granite County: 54.9 %Granite County54.9Hill County: 54.7 %Hill County54.7Blaine County: 54.7 %Blaine County54.7Big Horn County: 54.5 %Big Horn County54.5Madison County: 54 %Madison County54Jefferson County: 53.7 %Jefferson County53.7Wibaux County: 53.5 %Wibaux County53.5Rosebud County: 53.5 %Rosebud County53.5Roosevelt County: 53.4 %Roosevelt County53.4Mineral County: 53.3 %Mineral County53.3Chouteau County: 53.3 %Chouteau County53.3Fallon County: 52.8 %Fallon County52.8Valley County: 52.7 %Valley County52.7Sheridan County: 52.7 %Sheridan County52.7Carbon County: 52.5 %Carbon County52.5Pondera County: 52.5 %Pondera County52.5Lake County: 52.4 %Lake County52.4Sweet Grass County: 52.4 %Sweet Grass County52.4Musselshell County: 52.2 %Musselshell County52.2Stillwater County: 51.9 %Stillwater County51.9Ravalli County: 51.8 %Ravalli County51.8Phillips County: 51.5 %Phillips County51.5Fergus County: 51.5 %Fergus County51.5Meagher County: 51.5 %Meagher County51.5Teton County: 51.5 %Teton County51.5McCone County: 51.1 %McCone County51.1Daniels County: 50.5 %Daniels County50.5Lincoln County: 50.4 %Lincoln County50.4Judith Basin County: 50.3 %Judith Basin County50.3Liberty County: 50.1 %Liberty County50.1Wheatland County: 50.1 %Wheatland County50.1Carter County: 49.9 %Carter County49.9Sanders County: 49.1 %Sanders County49.1Garfield County: 48.9 %Garfield County48.9Petroleum County: 48.9 %Petroleum County48.9Powder River County: 48.7 %Powder River County48.7Golden Valley County: 48 %Golden Valley County48Treasure County: 46 %Treasure County46Prairie County: 41.8 %Prairie County41.8Gallatin County: 67.3 %Gallatin County67.3Missoula County: 62.8 %Missoula County62.8Toole County: 60.9 %Toole County60.9Powell County: 60.4 %Powell County60.4Park County: 58.7 %Park County58.7Silver Bow County: 58.6 %Silver Bow County58.6Yellowstone County: 58.2 %Yellowstone County58.2Cascade County: 57.8 %Cascade County57.8Lewis and Clark County: 57.7 %Lewis and Clark County57.7Richland County: 57.2 %Richland County57.2Beaverhead County: 57.1 %Beaverhead County57.1Custer County: 56.8 %Custer County56.8Deer Lodge County: 56.6 %Deer Lodge County56.6Glacier County: 56.2 %Glacier County56.2Dawson County: 56 %Dawson County56Flathead County: 55.8 %Flathead County55.8Broadwater County: 55.4 %Broadwater County55.4Granite County: 54.9 %Granite County54.9Hill County: 54.7 %Hill County54.7Blaine County: 54.7 %Blaine County54.7Big Horn County: 54.5 %Big Horn County54.5Madison County: 54 %Madison County54Jefferson County: 53.7 %Jefferson County53.7Wibaux County: 53.5 %Wibaux County53.5Rosebud County: 53.5 %Rosebud County53.5Roosevelt County: 53.4 %Roosevelt County53.4Mineral County: 53.3 %Mineral County53.3Chouteau County: 53.3 %Chouteau County53.3Fallon County: 52.8 %Fallon County52.8Valley County: 52.7 %Valley County52.7Sheridan County: 52.7 %Sheridan County52.7Carbon County: 52.5 %Carbon County52.5Pondera County: 52.5 %Pondera County52.5Lake County: 52.4 %Lake County52.4Sweet Grass County: 52.4 %Sweet Grass County52.4Musselshell County: 52.2 %Musselshell County52.2Stillwater County: 51.9 %Stillwater County51.9Ravalli County: 51.8 %Ravalli County51.8Phillips County: 51.5 %Phillips County51.5Fergus County: 51.5 %Fergus County51.5Meagher County: 51.5 %Meagher County51.5Teton County: 51.5 %Teton County51.5McCone County: 51.1 %McCone County51.1Daniels County: 50.5 %Daniels County50.5Lincoln County: 50.4 %Lincoln County50.4Judith Basin County: 50.3 %Judith Basin County50.3Liberty County: 50.1 %Liberty County50.1Wheatland County: 50.1 %Wheatland County50.1Carter County: 49.9 %Carter County49.9Sanders County: 49.1 %Sanders County49.1Garfield County: 48.9 %Garfield County48.9Petroleum County: 48.9 %Petroleum County48.9Powder River County: 48.7 %Powder River County48.7Golden Valley County: 48 %Golden Valley County48Treasure County: 46 %Treasure County46Prairie County: 41.8 %Prairie County41.8
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2024 (%)Change on 2023
1Gallatin County67.30 pts
2Missoula County62.80 pts
3Toole County60.9-0.3 pts
4Powell County60.4-1.1 pts
5Park County58.7-0.2 pts
6Silver Bow County58.6-0.3 pts
7Yellowstone County58.2-0.2 pts
8Cascade County57.8+0.1 pts
9Lewis and Clark County57.7-0.3 pts
10Richland County57.2-0.7 pts
11Beaverhead County57.1+0.2 pts
12Custer County56.8-0.4 pts
13Deer Lodge County56.6-0.9 pts
14Glacier County56.2-0.2 pts
15Dawson County56-0.4 pts
16Flathead County55.8-0.2 pts
17Broadwater County55.4-0.5 pts
18Granite County54.9+0.6 pts
19Hill County54.7-0.2 pts
20Blaine County54.7-0.4 pts
21Big Horn County54.5+0.1 pts
22Madison County54+0.3 pts
23Jefferson County53.7-0.2 pts
24Wibaux County53.50 pts
25Rosebud County53.5+0.3 pts
26Roosevelt County53.4-0.1 pts
27Mineral County53.3+0.2 pts
28Chouteau County53.3-0.2 pts
29Fallon County52.8-0.7 pts
30Valley County52.7-0.2 pts
31Sheridan County52.7+0.6 pts
32Carbon County52.5-1 pts
33Pondera County52.5-0.2 pts
34Lake County52.4-0.2 pts
35Sweet Grass County52.4-0.4 pts
36Musselshell County52.2-0.5 pts
37Stillwater County51.9-0.7 pts
38Ravalli County51.8-0.3 pts
39Phillips County51.5-0.4 pts
40Fergus County51.5-0.2 pts
41Meagher County51.5-1.7 pts
42Teton County51.5-0.4 pts
43McCone County51.1-1 pts
44Daniels County50.5-0.6 pts
45Lincoln County50.4-0.1 pts
46Judith Basin County50.3-1.6 pts
47Liberty County50.1-0.1 pts
48Wheatland County50.1-0.9 pts
49Carter County49.9-0.6 pts
50Sanders County49.1-0.8 pts
51Garfield County48.9-0.3 pts
52Petroleum County48.9-1.5 pts
53Powder River County48.7-1.8 pts
54Golden Valley County48-0.9 pts
55Treasure County46-2.4 pts
56Prairie County41.8-1.5 pts

Other periods

About this ranking

Residents aged 18 to 64 as a percentage of total population on 1 July. United States: Census Bureau county population estimates by age; states and the nation are sums of their counties.

Not comparable with working-age shares for ages 15 to 64 used in EU and World Bank statistics.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties (Counties in Montana by population aged 18 to 64, 2024) [Data set]. Retrieved October 12, 2026, from https://www.census.gov/programs-surveys/popest/data/data-sets.html

MLA 9

Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Montana by population aged 18 to 64, 2024. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/population-18-64/montana-counties?period=2024. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Counties in Montana by population aged 18 to 64, 2024. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/population-18-64/montana-counties?period=2024.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Montana by population aged 18 to 64, 2024 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-18-64/montana-counties?period=2024 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_montana_by_2024,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Montana by population aged 18 to 64, 2024}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.census.gov/programs-surveys/popest/data/data-sets.html},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/population-18-64/montana-counties?period=2024. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Montana by population aged 18 to 64, 2024
PY  - 2026
DA  - 2026/06/25
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www.census.gov/programs-surveys/popest/data/data-sets.html
L2  - https://invokely.ai/rankings/population-18-64/montana-counties?period=2024
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/montana-counties?period=2024.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
ER  -
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Rank Counties in Montana by population aged 18 to 64 using official data, and cite the source.
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Questions

Which county has the highest population aged 18 to 64?

Gallatin County, with 67.3% in 2024, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Prairie County, with 41.8% in 2024.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Retrieved 2026-10-12.

Population aged 18 to 64: other rankings

Counties in Montana: more rankings