Data / Rankings / Population aged 65 and over / Counties in Montana

Counties in Montana by share of population aged 65 and over

Prairie County had the highest share of population aged 65 and over of 56 counties in 2021, at 33.8%. Big Horn County had the lowest, at 13.4%. The median was 24.7% and the figure for Montana was 20.3%. Source: the U.S. Census Bureau.

Highest33.8Prairie County
Lowest13.4Big Horn County
Median24.756 counties
Montana20.3History

All counties, 2021

CSVChart (SVG)

Prairie CountyPrairie County: 33.8 %33.8Sanders CountySanders County: 32.7 %32.7Petroleum CountyPetroleum County: 31.9 %31.9Lincoln CountyLincoln County: 30.8 %30.8Madison CountyMadison County: 30.4 %30.4Golden Valley CountyGolden Valley County: 29.8 %29.8Judith Basin CountyJudith Basin County: 29.6 %29.6Powder River CountyPowder River County: 29.2 %29.2Meagher CountyMeagher County: 28.9 %28.9Granite CountyGranite County: 28.6 %28.6Ravalli CountyRavalli County: 27.9 %27.9Sweet Grass CountySweet Grass County: 27.8 %27.8Mineral CountyMineral County: 27.7 %27.7Carter CountyCarter County: 27.4 %27.4Treasure CountyTreasure County: 27.1 %27.1Musselshell CountyMusselshell County: 26.9 %26.9Wibaux CountyWibaux County: 26.7 %26.7Fergus CountyFergus County: 26.5 %26.5Carbon CountyCarbon County: 26.5 %26.5Deer Lodge CountyDeer Lodge County: 26.4 %26.4Wheatland CountyWheatland County: 26.2 %26.2Garfield CountyGarfield County: 26.1 %26.1Sheridan CountySheridan County: 26.1 %26.1Daniels CountyDaniels County: 25.9 %25.9McCone CountyMcCone County: 25.8 %25.8Stillwater CountyStillwater County: 25.4 %25.4Lake CountyLake County: 24.9 %24.9Beaverhead CountyBeaverhead County: 24.7 %24.7Jefferson CountyJefferson County: 24.7 %24.7Liberty CountyLiberty County: 24.5 %24.5Phillips CountyPhillips County: 24.3 %24.3Teton CountyTeton County: 24.3 %24.3Park CountyPark County: 23.6 %23.6Valley CountyValley County: 23.5 %23.5Pondera CountyPondera County: 22.8 %22.8Broadwater CountyBroadwater County: 22.7 %22.7Powell CountyPowell County: 22.4 %22.4Chouteau CountyChouteau County: 22.2 %22.2Flathead CountyFlathead County: 21.8 %21.8Dawson CountyDawson County: 21.1 %21.1Silver Bow CountySilver Bow County: 20.9 %20.9Custer CountyCuster County: 20.8 %20.8Lewis and Clark CountyLewis and Clark County: 20.1 %20.1Cascade CountyCascade County: 19.6 %19.6Fallon CountyFallon County: 18.9 %18.9Toole CountyToole County: 18.8 %18.8Yellowstone CountyYellowstone County: 18.2 %18.2Missoula CountyMissoula County: 18 %18Rosebud CountyRosebud County: 17.7 %17.7Richland CountyRichland County: 16.7 %16.7Hill CountyHill County: 16.6 %16.6Blaine CountyBlaine County: 16.3 %16.3Roosevelt CountyRoosevelt County: 13.7 %13.7Gallatin CountyGallatin County: 13.6 %13.6Glacier CountyGlacier County: 13.4 %13.4Big Horn CountyBig Horn County: 13.4 %13.4
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09.

Full ranking

RankCounties2021 (%)Change on 2020
1Prairie County33.8+0.9 pts
2Sanders County32.7+0.3 pts
3Petroleum County31.9-0.5 pts
4Lincoln County30.8+0.3 pts
5Madison County30.4+0.1 pts
6Golden Valley County29.8-0 pts
7Judith Basin County29.6+1 pts
8Powder River County29.2+0.4 pts
9Meagher County28.9+0.7 pts
10Granite County28.6-0.3 pts
11Ravalli County27.9-0.1 pts
12Sweet Grass County27.8+0.6 pts
13Mineral County27.7-0.3 pts
14Carter County27.4+0.7 pts
15Treasure County27.1+0.4 pts
16Musselshell County26.9-0.2 pts
17Wibaux County26.7-0.4 pts
18Fergus County26.5+0.1 pts
19Carbon County26.5+0.6 pts
20Deer Lodge County26.4+0.4 pts
21Wheatland County26.2+1.1 pts
22Garfield County26.1-1.3 pts
23Sheridan County26.1+1.1 pts
24Daniels County25.9+0.3 pts
25McCone County25.8+1.4 pts
26Stillwater County25.4+0.7 pts
27Lake County24.9+0.6 pts
28Beaverhead County24.7+0.3 pts
29Jefferson County24.7+0.6 pts
30Liberty County24.5-0.2 pts
31Phillips County24.3+0.7 pts
32Teton County24.3+0.6 pts
33Park County23.6+0.3 pts
34Valley County23.5+0.5 pts
35Pondera County22.8+0.2 pts
36Broadwater County22.7-0.1 pts
37Powell County22.4+0.4 pts
38Chouteau County22.2+0.7 pts
39Flathead County21.8+0.2 pts
40Dawson County21.1+0.3 pts
41Silver Bow County20.9+0.2 pts
42Custer County20.8+0.2 pts
43Lewis and Clark County20.1+0.5 pts
44Cascade County19.6+0.4 pts
45Fallon County18.9+0.7 pts
46Toole County18.8+0.5 pts
47Yellowstone County18.2+0.3 pts
48Missoula County18+0.4 pts
49Rosebud County17.7+0.3 pts
50Richland County16.7+1 pts
51Hill County16.6+0.5 pts
52Blaine County16.3+0.4 pts
53Roosevelt County13.70 pts
54Gallatin County13.6+0.3 pts
55Glacier County13.4+0.4 pts
56Big Horn County13.4-0.1 pts

Other periods

About this ranking

Residents aged 65 or over as a percentage of total population. Spain: 1 January, INE annual census. United States: 1 July, Census Bureau population estimates. World Bank figures for other countries and the World refer to mid-year.

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 (cc-est agesex): residents aged 65 and over as a percentage of the total, 1 July; states and the nation summed from counties. https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/counties/asrh/cc-est2025-agesex-all.csv. Retrieved 2026-10-09.

Use this data in your AI agent

Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:

Rank Counties in Montana by share of population aged 65 and over using official data, and cite the source.
rank_places {"indicator":"population_65_plus_share","level":"province","within":"Montana","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=population_65_plus_share&level=province&within=Montana&limit=10

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Questions

Which county has the highest share of population aged 65 and over?

Prairie County, with 33.8% in 2021, according to the U.S. Census Bureau.

Which county has the lowest share of population aged 65 and over?

Big Horn County, with 13.4% in 2021.

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 (cc-est agesex): residents aged 65 and over as a percentage of the total, 1 July; states and the nation summed from counties. Retrieved 2026-10-09.

Population aged 65 and over: other rankings

Counties in Montana: more rankings