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

Counties in Idaho by share of population aged 65 and over, 2025

Custer County had the highest share of population aged 65 and over of 44 counties in 2025, at 32.8%. Madison County had the lowest, at 6.6%. The median was 21.3% and the figure for Idaho was 18.7%. Source: the U.S. Census Bureau.

Highest32.8Custer County
Lowest6.6Madison County
Median21.344 counties
Idaho18.7History

All counties, 2025

CSVChart (SVG)

Custer CountyCuster County: 32.8 %32.8Lemhi CountyLemhi County: 32.8 %32.8Idaho CountyIdaho County: 32.6 %32.6Adams CountyAdams County: 32.5 %32.5Boise CountyBoise County: 31.1 %31.1Clearwater CountyClearwater County: 31.1 %31.1Lewis CountyLewis County: 29.6 %29.6Valley CountyValley County: 29.6 %29.6Camas CountyCamas County: 29.6 %29.6Bonner CountyBonner County: 28.3 %28.3Benewah CountyBenewah County: 27.2 %27.2Washington CountyWashington County: 26.5 %26.5Blaine CountyBlaine County: 26.1 %26.1Boundary CountyBoundary County: 26 %26Shoshone CountyShoshone County: 25.9 %25.9Butte CountyButte County: 25.9 %25.9Gem CountyGem County: 25.1 %25.1Bear Lake CountyBear Lake County: 24 %24Nez Perce CountyNez Perce County: 22.9 %22.9Kootenai CountyKootenai County: 22.4 %22.4Payette CountyPayette County: 21.7 %21.7Clark CountyClark County: 21.5 %21.5Oneida CountyOneida County: 21.1 %21.1Owyhee CountyOwyhee County: 20.1 %20.1Fremont CountyFremont County: 19.7 %19.7Gooding CountyGooding County: 19.3 %19.3Caribou CountyCaribou County: 19.1 %19.1Ada CountyAda County: 18.1 %18.1Twin Falls CountyTwin Falls County: 17.9 %17.9Minidoka CountyMinidoka County: 17.8 %17.8Power CountyPower County: 17.3 %17.3Lincoln CountyLincoln County: 17.1 %17.1Bannock CountyBannock County: 16.9 %16.9Bingham CountyBingham County: 16.8 %16.8Latah CountyLatah County: 16.7 %16.7Elmore CountyElmore County: 16.6 %16.6Teton CountyTeton County: 16.1 %16.1Franklin CountyFranklin County: 16 %16Cassia CountyCassia County: 15.9 %15.9Canyon CountyCanyon County: 15.7 %15.7Bonneville CountyBonneville County: 15 %15Jerome CountyJerome County: 14.7 %14.7Jefferson CountyJefferson County: 13.8 %13.8Madison CountyMadison County: 6.6 %6.6
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09.

Full ranking

RankCounties2025 (%)Change on 2024
1Custer County32.8+0.6 pts
2Lemhi County32.8+0.2 pts
3Idaho County32.6+0.9 pts
4Adams County32.5+1 pts
5Boise County31.1+1 pts
6Clearwater County31.1+0.7 pts
7Lewis County29.6+0.8 pts
8Valley County29.6+0.8 pts
9Camas County29.6+0.5 pts
10Bonner County28.3+0.5 pts
11Benewah County27.2+0.6 pts
12Washington County26.5+0.4 pts
13Blaine County26.1+0.9 pts
14Boundary County26+0.3 pts
15Shoshone County25.9+0.2 pts
16Butte County25.9+0.6 pts
17Gem County25.1+0.4 pts
18Bear Lake County24+0.7 pts
19Nez Perce County22.9+0.3 pts
20Kootenai County22.4+0.4 pts
21Payette County21.7+0.5 pts
22Clark County21.5+0.5 pts
23Oneida County21.1+0.1 pts
24Owyhee County20.1+0.8 pts
25Fremont County19.7+0.6 pts
26Gooding County19.3+0.5 pts
27Caribou County19.10 pts
28Ada County18.1+0.4 pts
29Twin Falls County17.9+0.3 pts
30Minidoka County17.8+0.3 pts
31Power County17.3+0.4 pts
32Lincoln County17.1+0.3 pts
33Bannock County16.9+0.3 pts
34Bingham County16.8+0.4 pts
35Latah County16.7+0.5 pts
36Elmore County16.6+0.6 pts
37Teton County16.1+0.8 pts
38Franklin County16+0.2 pts
39Cassia County15.9+0.1 pts
40Canyon County15.7+0.2 pts
41Bonneville County15+0.3 pts
42Jerome County14.7+0.3 pts
43Jefferson County13.8+0.6 pts
44Madison County6.6+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

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Rank Counties in Idaho 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":"Idaho","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=population_65_plus_share&level=province&within=Idaho&limit=10

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Questions

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

Custer County, with 32.8% in 2025, according to the U.S. Census Bureau.

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

Madison County, with 6.6% in 2025.

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 Idaho: more rankings