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

Counties in Idaho by population aged 18 to 64

Madison County had the highest population aged 18 to 64 of 44 counties in 2023, at 72.1%. Idaho County had the lowest, at 49.2%. The median was 54.3% and the figure for Idaho was 58%. Source: the U.S. Census Bureau.

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Highest72.1Madison County
Lowest49.2Idaho County
Median54.344 counties
Idaho58History

Map of counties, 2023

Ada County: 61 %Adams County: 51.2 %Bannock County: 58.6 %Bear Lake County: 51.1 %Benewah County: 51.5 %Bingham County: 55.2 %Blaine County: 56.5 %Boise County: 54.4 %Bonner County: 53.1 %Bonneville County: 56.4 %Boundary County: 50.6 %Butte County: 51.6 %Camas County: 51.7 %Canyon County: 58.1 %Caribou County: 52.7 %Cassia County: 53.8 %Clark County: 53 %Clearwater County: 54 %Custer County: 51.7 %Elmore County: 60.5 %Franklin County: 54.2 %Fremont County: 55.5 %Gem County: 53.6 %Gooding County: 55.6 %Idaho County: 49.2 %Jefferson County: 55.2 %Jerome County: 56.1 %Kootenai County: 56.1 %Latah County: 64.2 %Lemhi County: 49.9 %Lewis County: 51.2 %Lincoln County: 56.7 %Madison County: 72.1 %Minidoka County: 55.1 %Nez Perce County: 56.8 %Oneida County: 51.5 %Owyhee County: 55.9 %Payette County: 54.1 %Power County: 54.5 %Shoshone County: 54.3 %Teton County: 62.7 %Twin Falls County: 56.6 %Valley County: 53.5 %Washington County: 52 %
  • Under 52
  • 52 to 53
  • 53 to 54
  • 54 to 56
  • 56 to 57
  • 57 and over
%, 2023. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2023

Madison County: 72.1 %Madison County72.1Latah County: 64.2 %Latah County64.2Teton County: 62.7 %Teton County62.7Ada County: 61 %Ada County61Elmore County: 60.5 %Elmore County60.5Bannock County: 58.6 %Bannock County58.6Canyon County: 58.1 %Canyon County58.1Nez Perce County: 56.8 %Nez Perce County56.8Lincoln County: 56.7 %Lincoln County56.7Twin Falls County: 56.6 %Twin Falls County56.6Blaine County: 56.5 %Blaine County56.5Bonneville County: 56.4 %Bonneville County56.4Kootenai County: 56.1 %Kootenai County56.1Jerome County: 56.1 %Jerome County56.1Owyhee County: 55.9 %Owyhee County55.9Gooding County: 55.6 %Gooding County55.6Fremont County: 55.5 %Fremont County55.5Jefferson County: 55.2 %Jefferson County55.2Bingham County: 55.2 %Bingham County55.2Minidoka County: 55.1 %Minidoka County55.1Power County: 54.5 %Power County54.5Boise County: 54.4 %Boise County54.4Shoshone County: 54.3 %Shoshone County54.3Franklin County: 54.2 %Franklin County54.2Payette County: 54.1 %Payette County54.1Clearwater County: 54 %Clearwater County54Cassia County: 53.8 %Cassia County53.8Gem County: 53.6 %Gem County53.6Valley County: 53.5 %Valley County53.5Bonner County: 53.1 %Bonner County53.1Clark County: 53 %Clark County53Caribou County: 52.7 %Caribou County52.7Washington County: 52 %Washington County52Camas County: 51.7 %Camas County51.7Custer County: 51.7 %Custer County51.7Butte County: 51.6 %Butte County51.6Benewah County: 51.5 %Benewah County51.5Oneida County: 51.5 %Oneida County51.5Adams County: 51.2 %Adams County51.2Lewis County: 51.2 %Lewis County51.2Bear Lake County: 51.1 %Bear Lake County51.1Boundary County: 50.6 %Boundary County50.6Lemhi County: 49.9 %Lemhi County49.9Idaho County: 49.2 %Idaho County49.2Madison County: 72.1 %Madison County72.1Latah County: 64.2 %Latah County64.2Teton County: 62.7 %Teton County62.7Ada County: 61 %Ada County61Elmore County: 60.5 %Elmore County60.5Bannock County: 58.6 %Bannock County58.6Canyon County: 58.1 %Canyon County58.1Nez Perce County: 56.8 %Nez Perce County56.8Lincoln County: 56.7 %Lincoln County56.7Twin Falls County: 56.6 %Twin Falls County56.6Blaine County: 56.5 %Blaine County56.5Bonneville County: 56.4 %Bonneville County56.4Kootenai County: 56.1 %Kootenai County56.1Jerome County: 56.1 %Jerome County56.1Owyhee County: 55.9 %Owyhee County55.9Gooding County: 55.6 %Gooding County55.6Fremont County: 55.5 %Fremont County55.5Jefferson County: 55.2 %Jefferson County55.2Bingham County: 55.2 %Bingham County55.2Minidoka County: 55.1 %Minidoka County55.1Power County: 54.5 %Power County54.5Boise County: 54.4 %Boise County54.4Shoshone County: 54.3 %Shoshone County54.3Franklin County: 54.2 %Franklin County54.2Payette County: 54.1 %Payette County54.1Clearwater County: 54 %Clearwater County54Cassia County: 53.8 %Cassia County53.8Gem County: 53.6 %Gem County53.6Valley County: 53.5 %Valley County53.5Bonner County: 53.1 %Bonner County53.1Clark County: 53 %Clark County53Caribou County: 52.7 %Caribou County52.7Washington County: 52 %Washington County52Camas County: 51.7 %Camas County51.7Custer County: 51.7 %Custer County51.7Butte County: 51.6 %Butte County51.6Benewah County: 51.5 %Benewah County51.5Oneida County: 51.5 %Oneida County51.5Adams County: 51.2 %Adams County51.2Lewis County: 51.2 %Lewis County51.2Bear Lake County: 51.1 %Bear Lake County51.1Boundary County: 50.6 %Boundary County50.6Lemhi County: 49.9 %Lemhi County49.9Idaho County: 49.2 %Idaho County49.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2023 (%)Change on 2022
1Madison County72.1-0.4 pts
2Latah County64.2-0.5 pts
3Teton County62.7+0.2 pts
4Ada County61-0 pts
5Elmore County60.5-0.4 pts
6Bannock County58.6+0.1 pts
7Canyon County58.1+0.2 pts
8Nez Perce County56.8-0.1 pts
9Lincoln County56.7+0.2 pts
10Twin Falls County56.6+0.2 pts
11Blaine County56.5-0.4 pts
12Bonneville County56.4+0.2 pts
13Kootenai County56.1-0.3 pts
14Jerome County56.1-0.1 pts
15Owyhee County55.9+0.5 pts
16Gooding County55.6+0.7 pts
17Fremont County55.5+0.2 pts
18Jefferson County55.2+0.7 pts
19Bingham County55.2+0.4 pts
20Minidoka County55.10 pts
21Power County54.5+0.7 pts
22Boise County54.4-0.9 pts
23Shoshone County54.3-0.2 pts
24Franklin County54.2+0.6 pts
25Payette County54.1-0 pts
26Clearwater County54+0.2 pts
27Cassia County53.8+0.2 pts
28Gem County53.6-0 pts
29Valley County53.5-0.8 pts
30Bonner County53.1-0.4 pts
31Clark County53+0.1 pts
32Caribou County52.7-0 pts
33Washington County52+0.4 pts
34Camas County51.7-1.6 pts
35Custer County51.7-0.3 pts
36Butte County51.6-0.3 pts
37Benewah County51.5-0.5 pts
38Oneida County51.5-0.1 pts
39Adams County51.2-0.2 pts
40Lewis County51.2-0.1 pts
41Bear Lake County51.1+0.3 pts
42Boundary County50.6-0.1 pts
43Lemhi County49.9-0.2 pts
44Idaho County49.2-1 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 Idaho by population aged 18 to 64, 2023) [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 Idaho by population aged 18 to 64, 2023. 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/idaho-counties?period=2023. 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 Idaho by population aged 18 to 64, 2023. 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/idaho-counties?period=2023.

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 Idaho by population aged 18 to 64, 2023 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-18-64/idaho-counties?period=2023 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_idaho_by_2023,
  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 Idaho by population aged 18 to 64, 2023}},
  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/idaho-counties?period=2023. 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 Idaho by population aged 18 to 64, 2023
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/idaho-counties?period=2023
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/idaho-counties?period=2023.
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 Idaho 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?

Madison County, with 72.1% in 2023, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Idaho County, with 49.2% in 2023.

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 Idaho: more rankings