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 2017, at 72.2%. Oneida County had the lowest, at 51.2%. The median was 55.1% and the figure for Idaho was 58.4%. Source: the U.S. Census Bureau.

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Highest72.2Madison County
Lowest51.2Oneida County
Median55.144 counties
Idaho58.4History

Map of counties, 2017

Ada County: 61.3 %Adams County: 54.4 %Bannock County: 59.3 %Bear Lake County: 51.4 %Benewah County: 53.6 %Bingham County: 54.7 %Blaine County: 57.9 %Boise County: 58.2 %Bonner County: 56 %Bonneville County: 55.9 %Boundary County: 53.5 %Butte County: 53 %Camas County: 55.6 %Canyon County: 56.9 %Caribou County: 52.9 %Cassia County: 53.8 %Clark County: 57.1 %Clearwater County: 55.7 %Custer County: 55 %Elmore County: 61.4 %Franklin County: 52.6 %Fremont County: 54.6 %Gem County: 54.2 %Gooding County: 54.8 %Idaho County: 53.1 %Jefferson County: 53.8 %Jerome County: 56.2 %Kootenai County: 57.6 %Latah County: 67.4 %Lemhi County: 52.1 %Lewis County: 53.8 %Lincoln County: 55.1 %Madison County: 72.2 %Minidoka County: 55.5 %Nez Perce County: 58.6 %Oneida County: 51.2 %Owyhee County: 55.2 %Payette County: 54.4 %Power County: 53.8 %Shoshone County: 56.9 %Teton County: 61.9 %Twin Falls County: 56.6 %Valley County: 57.1 %Washington County: 51.8 %
  • Under 53
  • 53 to 54
  • 54 to 55
  • 55 to 56
  • 56 to 58
  • 58 and over
%, 2017. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2017

Madison County: 72.2 %Madison County72.2Latah County: 67.4 %Latah County67.4Teton County: 61.9 %Teton County61.9Elmore County: 61.4 %Elmore County61.4Ada County: 61.3 %Ada County61.3Bannock County: 59.3 %Bannock County59.3Nez Perce County: 58.6 %Nez Perce County58.6Boise County: 58.2 %Boise County58.2Blaine County: 57.9 %Blaine County57.9Kootenai County: 57.6 %Kootenai County57.6Valley County: 57.1 %Valley County57.1Clark County: 57.1 %Clark County57.1Shoshone County: 56.9 %Shoshone County56.9Canyon County: 56.9 %Canyon County56.9Twin Falls County: 56.6 %Twin Falls County56.6Jerome County: 56.2 %Jerome County56.2Bonner County: 56 %Bonner County56Bonneville County: 55.9 %Bonneville County55.9Clearwater County: 55.7 %Clearwater County55.7Camas County: 55.6 %Camas County55.6Minidoka County: 55.5 %Minidoka County55.5Owyhee County: 55.2 %Owyhee County55.2Lincoln County: 55.1 %Lincoln County55.1Custer County: 55 %Custer County55Gooding County: 54.8 %Gooding County54.8Bingham County: 54.7 %Bingham County54.7Fremont County: 54.6 %Fremont County54.6Payette County: 54.4 %Payette County54.4Adams County: 54.4 %Adams County54.4Gem County: 54.2 %Gem County54.2Jefferson County: 53.8 %Jefferson County53.8Cassia County: 53.8 %Cassia County53.8Lewis County: 53.8 %Lewis County53.8Power County: 53.8 %Power County53.8Benewah County: 53.6 %Benewah County53.6Boundary County: 53.5 %Boundary County53.5Idaho County: 53.1 %Idaho County53.1Butte County: 53 %Butte County53Caribou County: 52.9 %Caribou County52.9Franklin County: 52.6 %Franklin County52.6Lemhi County: 52.1 %Lemhi County52.1Washington County: 51.8 %Washington County51.8Bear Lake County: 51.4 %Bear Lake County51.4Oneida County: 51.2 %Oneida County51.2Madison County: 72.2 %Madison County72.2Latah County: 67.4 %Latah County67.4Teton County: 61.9 %Teton County61.9Elmore County: 61.4 %Elmore County61.4Ada County: 61.3 %Ada County61.3Bannock County: 59.3 %Bannock County59.3Nez Perce County: 58.6 %Nez Perce County58.6Boise County: 58.2 %Boise County58.2Blaine County: 57.9 %Blaine County57.9Kootenai County: 57.6 %Kootenai County57.6Valley County: 57.1 %Valley County57.1Clark County: 57.1 %Clark County57.1Shoshone County: 56.9 %Shoshone County56.9Canyon County: 56.9 %Canyon County56.9Twin Falls County: 56.6 %Twin Falls County56.6Jerome County: 56.2 %Jerome County56.2Bonner County: 56 %Bonner County56Bonneville County: 55.9 %Bonneville County55.9Clearwater County: 55.7 %Clearwater County55.7Camas County: 55.6 %Camas County55.6Minidoka County: 55.5 %Minidoka County55.5Owyhee County: 55.2 %Owyhee County55.2Lincoln County: 55.1 %Lincoln County55.1Custer County: 55 %Custer County55Gooding County: 54.8 %Gooding County54.8Bingham County: 54.7 %Bingham County54.7Fremont County: 54.6 %Fremont County54.6Payette County: 54.4 %Payette County54.4Adams County: 54.4 %Adams County54.4Gem County: 54.2 %Gem County54.2Jefferson County: 53.8 %Jefferson County53.8Cassia County: 53.8 %Cassia County53.8Lewis County: 53.8 %Lewis County53.8Power County: 53.8 %Power County53.8Benewah County: 53.6 %Benewah County53.6Boundary County: 53.5 %Boundary County53.5Idaho County: 53.1 %Idaho County53.1Butte County: 53 %Butte County53Caribou County: 52.9 %Caribou County52.9Franklin County: 52.6 %Franklin County52.6Lemhi County: 52.1 %Lemhi County52.1Washington County: 51.8 %Washington County51.8Bear Lake County: 51.4 %Bear Lake County51.4Oneida County: 51.2 %Oneida County51.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2017 (%)Change on 2016
1Madison County72.2+0.6 pts
2Latah County67.4-0.3 pts
3Teton County61.9+0.1 pts
4Elmore County61.4-0.4 pts
5Ada County61.3-0.2 pts
6Bannock County59.3-0.3 pts
7Nez Perce County58.6-0.1 pts
8Boise County58.2-0.5 pts
9Blaine County57.9-0.5 pts
10Kootenai County57.6-0.4 pts
11Valley County57.1-1.1 pts
12Clark County57.1+1.6 pts
13Shoshone County56.9-0.5 pts
14Canyon County56.9+0.1 pts
15Twin Falls County56.6-0.3 pts
16Jerome County56.2-0.1 pts
17Bonner County56-0.7 pts
18Bonneville County55.9-0.1 pts
19Clearwater County55.7-0.1 pts
20Camas County55.6-0.7 pts
21Minidoka County55.5-0.1 pts
22Owyhee County55.2-0.1 pts
23Lincoln County55.1+0.2 pts
24Custer County55-1.5 pts
25Gooding County54.8-0.6 pts
26Bingham County54.7-0.1 pts
27Fremont County54.6-0.1 pts
28Payette County54.4-0.1 pts
29Adams County54.4-1.1 pts
30Gem County54.20 pts
31Jefferson County53.8+0.1 pts
32Cassia County53.8+0.1 pts
33Lewis County53.8-0.3 pts
34Power County53.8-0.7 pts
35Benewah County53.6-0.2 pts
36Boundary County53.5-0.8 pts
37Idaho County53.1-1 pts
38Butte County53+0.4 pts
39Caribou County52.9-0.1 pts
40Franklin County52.6+0.2 pts
41Lemhi County52.1-0.4 pts
42Washington County51.8-0.6 pts
43Bear Lake County51.4-0.4 pts
44Oneida County51.2-0.6 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, 2017) [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, 2017. 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=2017. 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, 2017. 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=2017.

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, 2017 [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=2017 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_idaho_by_2017,
  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, 2017}},
  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=2017. 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, 2017
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=2017
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/idaho-counties?period=2017.
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 72.2% in 2017, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Oneida County, with 51.2% in 2017.

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