Data / Rankings / Median age on 1 July (US county estimates) / Counties in Idaho

Counties in Idaho by median age on 1 July (US county estimates)

Boise County had the highest median age on 1 July (US county estimates) of 44 counties in 2024, at 53.6 years. Madison County had the lowest, at 22.5 years. The median was 39.8 years. Source: the U.S. Census Bureau.

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Highest53.6Boise County
Lowest22.5Madison County
Median39.844 counties

Map of counties, 2024

Ada County: 38.9 yearsAdams County: 53 yearsBannock County: 35.4 yearsBear Lake County: 41.4 yearsBenewah County: 45.7 yearsBingham County: 35.5 yearsBlaine County: 46.1 yearsBoise County: 53.6 yearsBonner County: 48.1 yearsBonneville County: 34.1 yearsBoundary County: 45 yearsButte County: 45 yearsCamas County: 50 yearsCanyon County: 35 yearsCaribou County: 38 yearsCassia County: 33.1 yearsClark County: 39.7 yearsClearwater County: 51.8 yearsCuster County: 52.3 yearsElmore County: 34.1 yearsFranklin County: 34.4 yearsFremont County: 38 yearsGem County: 44.9 yearsGooding County: 37.8 yearsIdaho County: 50.5 yearsJefferson County: 33.5 yearsJerome County: 34.1 yearsKootenai County: 41.7 yearsLatah County: 31.3 yearsLemhi County: 52.4 yearsLewis County: 47.3 yearsLincoln County: 35.2 yearsMadison County: 22.5 yearsMinidoka County: 35.4 yearsNez Perce County: 42.1 yearsOneida County: 39.3 yearsOwyhee County: 39.1 yearsPayette County: 39.8 yearsPower County: 35.1 yearsShoshone County: 46 yearsTeton County: 40.3 yearsTwin Falls County: 36.8 yearsValley County: 49.7 yearsWashington County: 45.8 years
  • Under 35
  • 35 to 37
  • 37 to 40
  • 40 to 45
  • 45 to 49
  • 49 and over
years, 2024. Source: U.S. Census Bureau, Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2024

Boise County: 53.6 yearsBoise County53.6Adams County: 53 yearsAdams County53Lemhi County: 52.4 yearsLemhi County52.4Custer County: 52.3 yearsCuster County52.3Clearwater County: 51.8 yearsClearwater County51.8Idaho County: 50.5 yearsIdaho County50.5Camas County: 50 yearsCamas County50Valley County: 49.7 yearsValley County49.7Bonner County: 48.1 yearsBonner County48.1Lewis County: 47.3 yearsLewis County47.3Blaine County: 46.1 yearsBlaine County46.1Shoshone County: 46 yearsShoshone County46Washington County: 45.8 yearsWashington County45.8Benewah County: 45.7 yearsBenewah County45.7Boundary County: 45 yearsBoundary County45Butte County: 45 yearsButte County45Gem County: 44.9 yearsGem County44.9Nez Perce County: 42.1 yearsNez Perce County42.1Kootenai County: 41.7 yearsKootenai County41.7Bear Lake County: 41.4 yearsBear Lake County41.4Teton County: 40.3 yearsTeton County40.3Payette County: 39.8 yearsPayette County39.8Clark County: 39.7 yearsClark County39.7Oneida County: 39.3 yearsOneida County39.3Owyhee County: 39.1 yearsOwyhee County39.1Ada County: 38.9 yearsAda County38.9Caribou County: 38 yearsCaribou County38Fremont County: 38 yearsFremont County38Gooding County: 37.8 yearsGooding County37.8Twin Falls County: 36.8 yearsTwin Falls County36.8Bingham County: 35.5 yearsBingham County35.5Bannock County: 35.4 yearsBannock County35.4Minidoka County: 35.4 yearsMinidoka County35.4Lincoln County: 35.2 yearsLincoln County35.2Power County: 35.1 yearsPower County35.1Canyon County: 35 yearsCanyon County35Franklin County: 34.4 yearsFranklin County34.4Bonneville County: 34.1 yearsBonneville County34.1Elmore County: 34.1 yearsElmore County34.1Jerome County: 34.1 yearsJerome County34.1Jefferson County: 33.5 yearsJefferson County33.5Cassia County: 33.1 yearsCassia County33.1Latah County: 31.3 yearsLatah County31.3Madison County: 22.5 yearsMadison County22.5Boise County: 53.6 yearsBoise County53.6Adams County: 53 yearsAdams County53Lemhi County: 52.4 yearsLemhi County52.4Custer County: 52.3 yearsCuster County52.3Clearwater County: 51.8 yearsClearwater County51.8Idaho County: 50.5 yearsIdaho County50.5Camas County: 50 yearsCamas County50Valley County: 49.7 yearsValley County49.7Bonner County: 48.1 yearsBonner County48.1Lewis County: 47.3 yearsLewis County47.3Blaine County: 46.1 yearsBlaine County46.1Shoshone County: 46 yearsShoshone County46Washington County: 45.8 yearsWashington County45.8Benewah County: 45.7 yearsBenewah County45.7Boundary County: 45 yearsBoundary County45Butte County: 45 yearsButte County45Gem County: 44.9 yearsGem County44.9Nez Perce County: 42.1 yearsNez Perce County42.1Kootenai County: 41.7 yearsKootenai County41.7Bear Lake County: 41.4 yearsBear Lake County41.4Teton County: 40.3 yearsTeton County40.3Payette County: 39.8 yearsPayette County39.8Clark County: 39.7 yearsClark County39.7Oneida County: 39.3 yearsOneida County39.3Owyhee County: 39.1 yearsOwyhee County39.1Ada County: 38.9 yearsAda County38.9Caribou County: 38 yearsCaribou County38Fremont County: 38 yearsFremont County38Gooding County: 37.8 yearsGooding County37.8Twin Falls County: 36.8 yearsTwin Falls County36.8Bingham County: 35.5 yearsBingham County35.5Bannock County: 35.4 yearsBannock County35.4Minidoka County: 35.4 yearsMinidoka County35.4Lincoln County: 35.2 yearsLincoln County35.2Power County: 35.1 yearsPower County35.1Canyon County: 35 yearsCanyon County35Franklin County: 34.4 yearsFranklin County34.4Bonneville County: 34.1 yearsBonneville County34.1Elmore County: 34.1 yearsElmore County34.1Jerome County: 34.1 yearsJerome County34.1Jefferson County: 33.5 yearsJefferson County33.5Cassia County: 33.1 yearsCassia County33.1Latah County: 31.3 yearsLatah County31.3Madison County: 22.5 yearsMadison County22.5
years. Source: U.S. Census Bureau, Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Retrieved 2026-10-12.

Full ranking

RankCounties2024
years		Change on 2023
1Boise County53.6+0.6
2Adams County53-0.3
3Lemhi County52.4+0.2
4Custer County52.30
5Clearwater County51.8-0.1
6Idaho County50.50
7Camas County50+0.8
8Valley County49.70
9Bonner County48.1-0.3
10Lewis County47.3+0.1
11Blaine County46.1-0.3
12Shoshone County46+0.1
13Washington County45.8+0.8
14Benewah County45.7-0.2
15Boundary County45-0.3
15Butte County45+0.6
17Gem County44.9+0.6
18Nez Perce County42.1+0.2
19Kootenai County41.7+0.1
20Bear Lake County41.4+0.7
21Teton County40.3+0.2
22Payette County39.8+0.1
23Clark County39.7+1
24Oneida County39.3-0.2
25Owyhee County39.1+0.6
26Ada County38.9+0.3
27Caribou County38+0.4
27Fremont County38+0.4
29Gooding County37.80
30Twin Falls County36.8+0.1
31Bingham County35.5+0.2
32Bannock County35.4+0.3
32Minidoka County35.40
34Lincoln County35.2-0.8
35Power County35.1+0.2
36Canyon County350
37Franklin County34.4+0.1
38Bonneville County34.1+0.2
38Elmore County34.1+0.4
38Jerome County34.10
41Jefferson County33.5+0.5
42Cassia County33.1+0.1
43Latah County31.3+0.2
44Madison County22.50

Other periods

About this ranking

Age that divides the resident population of a US county into two halves of equal size on 1 July, from Census Bureau population estimates calculated by single year of age.

Counties only: the county file has no state or national medians, and medians cannot be added up. A single-year estimate, unlike median_age, which for US places is a five-year American Community Survey estimate.

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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. 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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage (Counties in Idaho by median age on 1 July (US county estimates), 2024) [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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage, Counties in Idaho by median age on 1 July (US county estimates), 2024. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/idaho-counties?period=2024. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Counties in Idaho by median age on 1 July (US county estimates), 2024. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/idaho-counties?period=2024.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage, Counties in Idaho by median age on 1 July (US county estimates), 2024 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/median-age-july-1-us-counties/idaho-counties?period=2024 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_idaho_by_2024,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: median age (MEDIAN\_AGE\_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage: Counties in Idaho by median age on 1 July (US county estimates), 2024}},
  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/median-age-july-1-us-counties/idaho-counties?period=2024. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: median age (MEDIAN\_AGE\_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. 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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage: Counties in Idaho by median age on 1 July (US county estimates), 2024
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/median-age-july-1-us-counties/idaho-counties?period=2024
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/idaho-counties?period=2024.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
ER  -
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Questions

Which county has the highest median age on 1 July (US county estimates)?

Boise County, with 53.6 years in 2024, according to the U.S. Census Bureau.

Which county has the lowest median age on 1 July (US county estimates)?

Madison County, with 22.5 years in 2024.

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: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Retrieved 2026-10-12.

Median age on 1 July (US county estimates): other rankings

Counties in Idaho: more rankings