Data / Population under 18 / Boulder County

Population under 18 in Boulder County

Population under 18 in Boulder County was 16.3% in 2025, according to the U.S. Census Bureau. That is down 0.4 pts from 2024. That is the 44th highest of 64 counties in 2025.

202516.3%
Change on 2024-0.4 pts
Rank44th of 64Counties in Colorado ranked
Series high21.32010
Series low16.32025

Next release: Friday, 25 June 2027, estimated by Invokely from past publication dates (low confidence), not announced by the publisher. Release calendar

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Population under 18 in Boulder County, 2010 to 2025

161718192021222010201320162019202220252010: 21.3 %2011: 21.1 %2012: 20.9 %2013: 20.7 %2014: 20.5 %2015: 20.2 %2016: 20 %2017: 19.7 %2018: 19.4 %2019: 19.2 %2020: 18.7 %2021: 18.4 %2022: 17.8 %2023: 17.2 %2024: 16.7 %2025: 16.3 %161820222010201620252010: 21.3 %2011: 21.1 %2012: 20.9 %2013: 20.7 %2014: 20.5 %2015: 20.2 %2016: 20 %2017: 19.7 %2018: 19.4 %2019: 19.2 %2020: 18.7 %2021: 18.4 %2022: 17.8 %2023: 17.2 %2024: 16.7 %2025: 16.3 %
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12, published 2026-06-25.
All 16 values
Period%
202516.3
202416.7
202317.2
202217.8
202118.4
202018.7
201919.2
201819.4
201719.7
201620
201520.2
201420.5
201320.7
201220.9
201121.1
201021.3

Compared with Colorado and United States

Place2025
Boulder County16.3
Colorado20.3
United States21.1

Boulder County compared with nearby places

Adams County: 23.3 %Alamosa County: 23.1 %Arapahoe County: 22.1 %Archuleta County: 16.9 %Baca County: 22 %Bent County: 14.7 %Boulder County: 16.3 %Broomfield County: 18.7 %Chaffee County: 14.7 %Cheyenne County: 24.8 %Clear Creek County: 11.8 %Conejos County: 26 %Costilla County: 18.6 %Crowley County: 10 %Custer County: 16 %Delta County: 18.7 %Denver County: 18.3 %Dolores County: 16.7 %Douglas County: 22.3 %Eagle County: 18.8 %Elbert County: 21.3 %El Paso County: 22.2 %Fremont County: 14.8 %Garfield County: 22.8 %Gilpin County: 12.7 %Grand County: 14.9 %Gunnison County: 15.5 %Hinsdale County: 15.3 %Huerfano County: 14.5 %Jackson County: 15.9 %Jefferson County: 17.5 %Kiowa County: 24.7 %Kit Carson County: 24.9 %Lake County: 20.3 %La Plata County: 16.8 %Larimer County: 17.4 %Las Animas County: 16.5 %Lincoln County: 20.3 %Logan County: 18.4 %Mesa County: 19 %Mineral County: 11.4 %Moffat County: 22.8 %Montezuma County: 20.3 %Montrose County: 19.2 %Morgan County: 26.4 %Otero County: 22.3 %Ouray County: 12.6 %Park County: 14.8 %Phillips County: 24.6 %Pitkin County: 15.5 %Prowers County: 25.4 %Pueblo County: 21 %Rio Blanco County: 21.4 %Rio Grande County: 19.9 %Routt County: 17.6 %Saguache County: 18.1 %San Juan County: 11.6 %San Miguel County: 15.8 %Sedgwick County: 19.5 %Summit County: 15.9 %Teller County: 15.6 %Washington County: 22.5 %Weld County: 25.1 %Yuma County: 27.2 %
  • Under 15
  • 15 to 17
  • 17 to 19
  • 19 to 21
  • 21 to 23
  • 23 and over
Population under 18, 2025, %. Boulder County is outlined. Same source and period for every area shown. Source: U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Rankings

Definition

Residents aged 0 to 17 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.

Uses the US age of majority. Not comparable with population_0_14_share, which stops at 14.

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How to cite

U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 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 0 to 17 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 (Population under 18, Boulder County, 2010 to 2025) [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 0 to 17 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, Population under 18, Boulder County, 2010 to 2025. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/en/population-under-18/boulder-county-colorado. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 0 to 17 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. Population under 18, Boulder County, 2010 to 2025. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/en/population-under-18/boulder-county-colorado.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 0 to 17 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, Population under 18, Boulder County, 2010 to 2025 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/en/population-under-18/boulder-county-colorado (Accessed: 12 October 2026).

BibTeX
@misc{census_population_under_18_boulder_2025,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: residents aged 0 to 17 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: Population under 18, Boulder County, 2010 to 2025}},
  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/en/population-under-18/boulder-county-colorado. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 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 0 to 17 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: Population under 18, Boulder County, 2010 to 2025
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/en/population-under-18/boulder-county-colorado
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/population-under-18/boulder-county-colorado.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 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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Questions

What is the population under 18 in Boulder County?

Population under 18 in Boulder County was 16.3% in 2025, according to the U.S. Census Bureau. That is down 0.4 pts from 2024. That is the 44th highest of 64 counties in 2025.

Where does this figure come from?

U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 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 by Invokely on 2026-10-12.

What was the highest population under 18 in Boulder County?

21.3% in 2010, the highest value since 2010 in this series.

Related statistics for Boulder County

All statistics for Boulder County | Boulder County in figures