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

Counties in Idaho by share of population aged 65 and over

Lemhi County had the highest share of population aged 65 and over of 44 counties in 2021, at 31.1%. Madison County had the lowest, at 6.3%. The median was 19.8% and the figure for Idaho was 17.2%. Source: the U.S. Census Bureau.

Highest31.1Lemhi County
Lowest6.3Madison County
Median19.844 counties
Idaho17.2History

All counties, 2021

CSVChart (SVG)

Lemhi CountyLemhi County: 31.1 %31.1Adams CountyAdams County: 31.1 %31.1Custer CountyCuster County: 30.1 %30.1Idaho CountyIdaho County: 29.9 %29.9Clearwater CountyClearwater County: 29.3 %29.3Boise CountyBoise County: 27.4 %27.4Valley CountyValley County: 27 %27Bonner CountyBonner County: 26.8 %26.8Camas CountyCamas County: 26.6 %26.6Lewis CountyLewis County: 26.4 %26.4Washington CountyWashington County: 26 %26Boundary CountyBoundary County: 25.8 %25.8Benewah CountyBenewah County: 25.6 %25.6Shoshone CountyShoshone County: 25 %25Gem CountyGem County: 23.6 %23.6Butte CountyButte County: 23.3 %23.3Blaine CountyBlaine County: 22.9 %22.9Nez Perce CountyNez Perce County: 21.6 %21.6Oneida CountyOneida County: 21.3 %21.3Bear Lake CountyBear Lake County: 21.3 %21.3Kootenai CountyKootenai County: 20.8 %20.8Payette CountyPayette County: 20 %20Clark CountyClark County: 19.6 %19.6Fremont CountyFremont County: 18.6 %18.6Caribou CountyCaribou County: 18.3 %18.3Gooding CountyGooding County: 18.3 %18.3Owyhee CountyOwyhee County: 17.7 %17.7Twin Falls CountyTwin Falls County: 16.8 %16.8Power CountyPower County: 16.5 %16.5Lincoln CountyLincoln County: 16.4 %16.4Minidoka CountyMinidoka County: 16.3 %16.3Ada CountyAda County: 16.1 %16.1Bannock CountyBannock County: 15.6 %15.6Franklin CountyFranklin County: 15.6 %15.6Cassia CountyCassia County: 15.4 %15.4Bingham CountyBingham County: 15.3 %15.3Latah CountyLatah County: 15.2 %15.2Canyon CountyCanyon County: 15 %15Elmore CountyElmore County: 14.4 %14.4Jerome CountyJerome County: 14 %14Bonneville CountyBonneville County: 13.9 %13.9Teton CountyTeton County: 13.7 %13.7Jefferson CountyJefferson County: 12.5 %12.5Madison CountyMadison County: 6.3 %6.3
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09.

Full ranking

RankCounties2021 (%)Change on 2020
1Lemhi County31.1-0.1 pts
2Adams County31.1+0.4 pts
3Custer County30.1-0.1 pts
4Idaho County29.9+0.3 pts
5Clearwater County29.3+0.4 pts
6Boise County27.4+0.3 pts
7Valley County27+0.5 pts
8Bonner County26.8+0.3 pts
9Camas County26.6+2.3 pts
10Lewis County26.4+0.2 pts
11Washington County26-0.1 pts
12Boundary County25.8-0.1 pts
13Benewah County25.6+0.3 pts
14Shoshone County25-0.4 pts
15Gem County23.6+0.3 pts
16Butte County23.3+1 pts
17Blaine County22.9+0.9 pts
18Nez Perce County21.6+0.4 pts
19Oneida County21.3+0.6 pts
20Bear Lake County21.3-0.3 pts
21Kootenai County20.8+0.1 pts
22Payette County20+0.3 pts
23Clark County19.6+0.8 pts
24Fremont County18.6+0.3 pts
25Caribou County18.3+0.5 pts
26Gooding County18.3+0.4 pts
27Owyhee County17.7-0 pts
28Twin Falls County16.8+0.3 pts
29Power County16.5+0.1 pts
30Lincoln County16.4-0.1 pts
31Minidoka County16.3+0.3 pts
32Ada County16.1+0.4 pts
33Bannock County15.6+0.3 pts
34Franklin County15.6+0.3 pts
35Cassia County15.4+0.3 pts
36Bingham County15.3+0.3 pts
37Latah County15.2+0.4 pts
38Canyon County15+0.1 pts
39Elmore County14.4+0.4 pts
40Jerome County14+0.2 pts
41Bonneville County13.9+0.1 pts
42Teton County13.7+0.5 pts
43Jefferson County12.5+0.2 pts
44Madison County6.3+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.

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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}
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Questions

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

Lemhi County, with 31.1% in 2021, according to the U.S. Census Bureau.

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

Madison County, with 6.3% 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 Idaho: more rankings