Counties in Montana by median age on 1 July (US county estimates)

Petroleum County had the highest median age on 1 July (US county estimates) of 56 counties in 2022, at 55.4 years. Big Horn County had the lowest, at 32.1 years. The median was 44.8 years. Source: the U.S. Census Bureau.

Keep it in a collection in your library.
Highest55.4Petroleum County
Lowest32.1Big Horn County
Median44.856 counties

Map of counties, 2022

Beaverhead County: 43.8 yearsBig Horn County: 32.1 yearsBlaine County: 35.5 yearsBroadwater County: 44.6 yearsCarbon County: 49.2 yearsCarter County: 44.9 yearsCascade County: 38.9 yearsChouteau County: 42.9 yearsCuster County: 40.9 yearsDaniels County: 46.9 yearsDawson County: 42.1 yearsDeer Lodge County: 50.1 yearsFallon County: 39.3 yearsFergus County: 46.6 yearsFlathead County: 42.3 yearsGallatin County: 33.9 yearsGarfield County: 43.4 yearsGlacier County: 33.8 yearsGolden Valley County: 51 yearsGranite County: 52.4 yearsHill County: 35.3 yearsJefferson County: 47.8 yearsJudith Basin County: 51 yearsLake County: 44.7 yearsLewis and Clark County: 41.4 yearsLiberty County: 42.1 yearsLincoln County: 52.6 yearsMcCone County: 47.5 yearsMadison County: 52.1 yearsMeagher County: 50.9 yearsMineral County: 51.8 yearsMissoula County: 38.1 yearsMusselshell County: 48.7 yearsPark County: 46.4 yearsPetroleum County: 55.4 yearsPhillips County: 44.3 yearsPondera County: 41.4 yearsPowder River County: 50.3 yearsPowell County: 46.1 yearsPrairie County: 53.3 yearsRavalli County: 49.3 yearsRichland County: 39.5 yearsRoosevelt County: 32.3 yearsRosebud County: 37.7 yearsSanders County: 54.6 yearsSheridan County: 45.7 yearsSilver Bow County: 41.6 yearsStillwater County: 48.1 yearsSweet Grass County: 48.6 yearsTeton County: 44 yearsToole County: 39.2 yearsTreasure County: 44.8 yearsValley County: 44.3 yearsWheatland County: 47.1 yearsWibaux County: 48.2 yearsYellowstone County: 39 years
  • Under 39
  • 39 to 42
  • 42 to 45
  • 45 to 48
  • 48 to 51
  • 51 and over
years, 2022. Source: U.S. Census Bureau, Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2022

Petroleum County: 55.4 yearsPetroleum County55.4Sanders County: 54.6 yearsSanders County54.6Prairie County: 53.3 yearsPrairie County53.3Lincoln County: 52.6 yearsLincoln County52.6Granite County: 52.4 yearsGranite County52.4Madison County: 52.1 yearsMadison County52.1Mineral County: 51.8 yearsMineral County51.8Golden Valley County: 51 yearsGolden Valley County51Judith Basin County: 51 yearsJudith Basin County51Meagher County: 50.9 yearsMeagher County50.9Powder River County: 50.3 yearsPowder River County50.3Deer Lodge County: 50.1 yearsDeer Lodge County50.1Ravalli County: 49.3 yearsRavalli County49.3Carbon County: 49.2 yearsCarbon County49.2Musselshell County: 48.7 yearsMusselshell County48.7Sweet Grass County: 48.6 yearsSweet Grass County48.6Wibaux County: 48.2 yearsWibaux County48.2Stillwater County: 48.1 yearsStillwater County48.1Jefferson County: 47.8 yearsJefferson County47.8McCone County: 47.5 yearsMcCone County47.5Wheatland County: 47.1 yearsWheatland County47.1Daniels County: 46.9 yearsDaniels County46.9Fergus County: 46.6 yearsFergus County46.6Park County: 46.4 yearsPark County46.4Powell County: 46.1 yearsPowell County46.1Sheridan County: 45.7 yearsSheridan County45.7Carter County: 44.9 yearsCarter County44.9Treasure County: 44.8 yearsTreasure County44.8Lake County: 44.7 yearsLake County44.7Broadwater County: 44.6 yearsBroadwater County44.6Phillips County: 44.3 yearsPhillips County44.3Valley County: 44.3 yearsValley County44.3Teton County: 44 yearsTeton County44Beaverhead County: 43.8 yearsBeaverhead County43.8Garfield County: 43.4 yearsGarfield County43.4Chouteau County: 42.9 yearsChouteau County42.9Flathead County: 42.3 yearsFlathead County42.3Dawson County: 42.1 yearsDawson County42.1Liberty County: 42.1 yearsLiberty County42.1Silver Bow County: 41.6 yearsSilver Bow County41.6Lewis and Clark County: 41.4 yearsLewis and Clark County41.4Pondera County: 41.4 yearsPondera County41.4Custer County: 40.9 yearsCuster County40.9Richland County: 39.5 yearsRichland County39.5Fallon County: 39.3 yearsFallon County39.3Toole County: 39.2 yearsToole County39.2Yellowstone County: 39 yearsYellowstone County39Cascade County: 38.9 yearsCascade County38.9Missoula County: 38.1 yearsMissoula County38.1Rosebud County: 37.7 yearsRosebud County37.7Blaine County: 35.5 yearsBlaine County35.5Hill County: 35.3 yearsHill County35.3Gallatin County: 33.9 yearsGallatin County33.9Glacier County: 33.8 yearsGlacier County33.8Roosevelt County: 32.3 yearsRoosevelt County32.3Big Horn County: 32.1 yearsBig Horn County32.1Petroleum County: 55.4 yearsPetroleum County55.4Sanders County: 54.6 yearsSanders County54.6Prairie County: 53.3 yearsPrairie County53.3Lincoln County: 52.6 yearsLincoln County52.6Granite County: 52.4 yearsGranite County52.4Madison County: 52.1 yearsMadison County52.1Mineral County: 51.8 yearsMineral County51.8Golden Valley County: 51 yearsGolden Valley County51Judith Basin County: 51 yearsJudith Basin County51Meagher County: 50.9 yearsMeagher County50.9Powder River County: 50.3 yearsPowder River County50.3Deer Lodge County: 50.1 yearsDeer Lodge County50.1Ravalli County: 49.3 yearsRavalli County49.3Carbon County: 49.2 yearsCarbon County49.2Musselshell County: 48.7 yearsMusselshell County48.7Sweet Grass County: 48.6 yearsSweet Grass County48.6Wibaux County: 48.2 yearsWibaux County48.2Stillwater County: 48.1 yearsStillwater County48.1Jefferson County: 47.8 yearsJefferson County47.8McCone County: 47.5 yearsMcCone County47.5Wheatland County: 47.1 yearsWheatland County47.1Daniels County: 46.9 yearsDaniels County46.9Fergus County: 46.6 yearsFergus County46.6Park County: 46.4 yearsPark County46.4Powell County: 46.1 yearsPowell County46.1Sheridan County: 45.7 yearsSheridan County45.7Carter County: 44.9 yearsCarter County44.9Treasure County: 44.8 yearsTreasure County44.8Lake County: 44.7 yearsLake County44.7Broadwater County: 44.6 yearsBroadwater County44.6Phillips County: 44.3 yearsPhillips County44.3Valley County: 44.3 yearsValley County44.3Teton County: 44 yearsTeton County44Beaverhead County: 43.8 yearsBeaverhead County43.8Garfield County: 43.4 yearsGarfield County43.4Chouteau County: 42.9 yearsChouteau County42.9Flathead County: 42.3 yearsFlathead County42.3Dawson County: 42.1 yearsDawson County42.1Liberty County: 42.1 yearsLiberty County42.1Silver Bow County: 41.6 yearsSilver Bow County41.6Lewis and Clark County: 41.4 yearsLewis and Clark County41.4Pondera County: 41.4 yearsPondera County41.4Custer County: 40.9 yearsCuster County40.9Richland County: 39.5 yearsRichland County39.5Fallon County: 39.3 yearsFallon County39.3Toole County: 39.2 yearsToole County39.2Yellowstone County: 39 yearsYellowstone County39Cascade County: 38.9 yearsCascade County38.9Missoula County: 38.1 yearsMissoula County38.1Rosebud County: 37.7 yearsRosebud County37.7Blaine County: 35.5 yearsBlaine County35.5Hill County: 35.3 yearsHill County35.3Gallatin County: 33.9 yearsGallatin County33.9Glacier County: 33.8 yearsGlacier County33.8Roosevelt County: 32.3 yearsRoosevelt County32.3Big Horn County: 32.1 yearsBig Horn County32.1
years. Source: U.S. Census Bureau, Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Retrieved 2026-10-12.

Full ranking

RankCounties2022
years
Change on 2021
1Petroleum County55.4+0.7
2Sanders County54.6-0.4
3Prairie County53.3+0.2
4Lincoln County52.6-0.5
5Granite County52.4+0.9
6Madison County52.1-0.5
7Mineral County51.8-0.1
8Golden Valley County51-1.3
8Judith Basin County51-0.5
10Meagher County50.9-2.7
11Powder River County50.3-1
12Deer Lodge County50.1+0.1
13Ravalli County49.3-0.5
14Carbon County49.2-0.6
15Musselshell County48.7-1.4
16Sweet Grass County48.60
17Wibaux County48.2-1.6
18Stillwater County48.1-0.4
19Jefferson County47.8-1
20McCone County47.5+0.1
21Wheatland County47.10
22Daniels County46.9+0.9
23Fergus County46.6-0.3
24Park County46.4-0.3
25Powell County46.1+0.1
26Sheridan County45.7-0.7
27Carter County44.9+0.6
28Treasure County44.8+0.2
29Lake County44.7+0.1
30Broadwater County44.6-1.3
31Phillips County44.3-0.4
31Valley County44.30
33Teton County44-0.5
34Beaverhead County43.8+0.2
35Garfield County43.4+0.1
36Chouteau County42.9+0.6
37Flathead County42.3-0.2
38Dawson County42.1+0.5
38Liberty County42.1-0.7
40Silver Bow County41.60
41Lewis and Clark County41.4+0.1
41Pondera County41.4-0.5
43Custer County40.9-0.1
44Richland County39.5+0.6
45Fallon County39.3-0.2
46Toole County39.2-0.8
47Yellowstone County39+0.1
48Cascade County38.90
49Missoula County38.1+0.2
50Rosebud County37.70
51Blaine County35.5+0.6
52Hill County35.3+0.1
53Gallatin County33.9+0.2
54Glacier County33.8+0.3
55Roosevelt County32.3+0.2
56Big Horn County32.1+0.4

Other periods

About this ranking

Age that divides the resident population of a US county into two halves of equal size on 1 July, from Census Bureau population estimates calculated by single year of age.

Counties only: the county file has no state or national medians, and medians cannot be added up. A single-year estimate, unlike median_age, which for US places is a five-year American Community Survey estimate.

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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. 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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage (Counties in Montana by median age on 1 July (US county estimates), 2022) [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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage, Counties in Montana by median age on 1 July (US county estimates), 2022. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/montana-counties?period=2022. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Counties in Montana by median age on 1 July (US county estimates), 2022. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/montana-counties?period=2022.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage, Counties in Montana by median age on 1 July (US county estimates), 2022 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/median-age-july-1-us-counties/montana-counties?period=2022 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_montana_by_2022,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: median age (MEDIAN\_AGE\_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage: Counties in Montana by median age on 1 July (US county estimates), 2022}},
  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/median-age-july-1-us-counties/montana-counties?period=2022. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: median age (MEDIAN\_AGE\_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. 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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage: Counties in Montana by median age on 1 July (US county estimates), 2022
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/median-age-july-1-us-counties/montana-counties?period=2022
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/montana-counties?period=2022.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
ER  - 
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Questions

Which county has the highest median age on 1 July (US county estimates)?

Petroleum County, with 55.4 years in 2022, according to the U.S. Census Bureau.

Which county has the lowest median age on 1 July (US county estimates)?

Big Horn County, with 32.1 years in 2022.

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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Retrieved 2026-10-12.

Median age on 1 July (US county estimates): other rankings

Counties in Montana: more rankings