Data / Rankings / Population under 18 / Counties in Colorado

Counties in Colorado by population under 18

Conejos County had the highest population under 18 of 64 counties in 2017, at 27.5%. Crowley County had the lowest, at 11.2%. The median was 20.2% and the figure for Colorado was 22.7%. Source: the U.S. Census Bureau.

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Highest27.5Conejos County
Lowest11.2Crowley County
Median20.264 counties
Colorado22.7History

Map of counties, 2017

Adams County: 27 %Alamosa County: 23.9 %Arapahoe County: 24.2 %Archuleta County: 18.9 %Baca County: 21.2 %Bent County: 15.7 %Boulder County: 19.7 %Broomfield County: 23.6 %Chaffee County: 15.4 %Cheyenne County: 24.8 %Clear Creek County: 16.1 %Conejos County: 27.5 %Costilla County: 18.3 %Crowley County: 11.2 %Custer County: 15.5 %Delta County: 20.2 %Denver County: 19.9 %Dolores County: 18.7 %Douglas County: 27.4 %Eagle County: 23 %Elbert County: 22.1 %El Paso County: 24.3 %Fremont County: 16.2 %Garfield County: 25.5 %Gilpin County: 17.1 %Grand County: 17.4 %Gunnison County: 17.5 %Hinsdale County: 18.5 %Huerfano County: 16 %Jackson County: 16.3 %Jefferson County: 20.3 %Kiowa County: 22.8 %Kit Carson County: 25.3 %Lake County: 21.7 %La Plata County: 19.4 %Larimer County: 20.1 %Las Animas County: 18.4 %Lincoln County: 20.5 %Logan County: 18.8 %Mesa County: 21.8 %Mineral County: 13.3 %Moffat County: 25.6 %Montezuma County: 22 %Montrose County: 22.2 %Morgan County: 26.6 %Otero County: 23.6 %Ouray County: 15.7 %Park County: 16 %Phillips County: 24.3 %Pitkin County: 16.9 %Prowers County: 25.6 %Pueblo County: 22.7 %Rio Blanco County: 24.9 %Rio Grande County: 23.4 %Routt County: 19.7 %Saguache County: 21.3 %San Juan County: 13.3 %San Miguel County: 19.6 %Sedgwick County: 20 %Summit County: 17 %Teller County: 17.5 %Washington County: 23.2 %Weld County: 26.9 %Yuma County: 25.9 %
  • Under 16
  • 16 to 19
  • 19 to 20
  • 20 to 23
  • 23 to 25
  • 25 and over
%, 2017. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2017

Conejos County: 27.5 %Conejos County27.5Douglas County: 27.4 %Douglas County27.4Adams County: 27 %Adams County27Weld County: 26.9 %Weld County26.9Morgan County: 26.6 %Morgan County26.6Yuma County: 25.9 %Yuma County25.9Moffat County: 25.6 %Moffat County25.6Prowers County: 25.6 %Prowers County25.6Garfield County: 25.5 %Garfield County25.5Kit Carson County: 25.3 %Kit Carson County25.3Rio Blanco County: 24.9 %Rio Blanco County24.9Cheyenne County: 24.8 %Cheyenne County24.8Phillips County: 24.3 %Phillips County24.3El Paso County: 24.3 %El Paso County24.3Arapahoe County: 24.2 %Arapahoe County24.2Alamosa County: 23.9 %Alamosa County23.9Otero County: 23.6 %Otero County23.6Broomfield County: 23.6 %Broomfield County23.6Rio Grande County: 23.4 %Rio Grande County23.4Washington County: 23.2 %Washington County23.2Eagle County: 23 %Eagle County23Kiowa County: 22.8 %Kiowa County22.8Pueblo County: 22.7 %Pueblo County22.7Montrose County: 22.2 %Montrose County22.2Elbert County: 22.1 %Elbert County22.1Montezuma County: 22 %Montezuma County22Mesa County: 21.8 %Mesa County21.8Lake County: 21.7 %Lake County21.7Saguache County: 21.3 %Saguache County21.3Baca County: 21.2 %Baca County21.2Lincoln County: 20.5 %Lincoln County20.5Jefferson County: 20.3 %Jefferson County20.3Delta County: 20.2 %Delta County20.2Larimer County: 20.1 %Larimer County20.1Sedgwick County: 20 %Sedgwick County20Denver County: 19.9 %Denver County19.9Boulder County: 19.7 %Boulder County19.7Routt County: 19.7 %Routt County19.7San Miguel County: 19.6 %San Miguel County19.6La Plata County: 19.4 %La Plata County19.4Conejos County: 27.5 %Conejos County27.5Douglas County: 27.4 %Douglas County27.4Adams County: 27 %Adams County27Weld County: 26.9 %Weld County26.9Morgan County: 26.6 %Morgan County26.6Yuma County: 25.9 %Yuma County25.9Moffat County: 25.6 %Moffat County25.6Prowers County: 25.6 %Prowers County25.6Garfield County: 25.5 %Garfield County25.5Kit Carson County: 25.3 %Kit Carson County25.3Rio Blanco County: 24.9 %Rio Blanco County24.9Cheyenne County: 24.8 %Cheyenne County24.8Phillips County: 24.3 %Phillips County24.3El Paso County: 24.3 %El Paso County24.3Arapahoe County: 24.2 %Arapahoe County24.2Alamosa County: 23.9 %Alamosa County23.9Otero County: 23.6 %Otero County23.6Broomfield County: 23.6 %Broomfield County23.6Rio Grande County: 23.4 %Rio Grande County23.4Washington County: 23.2 %Washington County23.2Eagle County: 23 %Eagle County23Kiowa County: 22.8 %Kiowa County22.8Pueblo County: 22.7 %Pueblo County22.7Montrose County: 22.2 %Montrose County22.2Elbert County: 22.1 %Elbert County22.1Montezuma County: 22 %Montezuma County22Mesa County: 21.8 %Mesa County21.8Lake County: 21.7 %Lake County21.7Saguache County: 21.3 %Saguache County21.3Baca County: 21.2 %Baca County21.2Lincoln County: 20.5 %Lincoln County20.5Jefferson County: 20.3 %Jefferson County20.3Delta County: 20.2 %Delta County20.2Larimer County: 20.1 %Larimer County20.1Sedgwick County: 20 %Sedgwick County20Denver County: 19.9 %Denver County19.9Boulder County: 19.7 %Boulder County19.7Routt County: 19.7 %Routt County19.7San Miguel County: 19.6 %San Miguel County19.6La Plata County: 19.4 %La Plata County19.4
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2017 (%)Change on 2016
1Conejos County27.50 pts
2Douglas County27.4-0.6 pts
3Adams County27-0.4 pts
4Weld County26.9-0.1 pts
5Morgan County26.6-0.3 pts
6Yuma County25.9-0 pts
7Moffat County25.6+0.1 pts
8Prowers County25.6+0.1 pts
9Garfield County25.5-0.2 pts
10Kit Carson County25.3+1.3 pts
11Rio Blanco County24.9+0.1 pts
12Cheyenne County24.8-0.8 pts
13Phillips County24.3+0.1 pts
14El Paso County24.3-0.2 pts
15Arapahoe County24.2-0.2 pts
16Alamosa County23.9+0.1 pts
17Otero County23.6-0.1 pts
18Broomfield County23.6-0.3 pts
19Rio Grande County23.4-0.5 pts
20Washington County23.2-0 pts
21Eagle County23-0.1 pts
22Kiowa County22.8+0.8 pts
23Pueblo County22.7-0.3 pts
24Montrose County22.2-0.1 pts
25Elbert County22.1-0 pts
26Montezuma County22-0.2 pts
27Mesa County21.8-0.2 pts
28Lake County21.7-0.3 pts
29Saguache County21.3-0.9 pts
30Baca County21.2+0.6 pts
31Lincoln County20.5-0 pts
32Jefferson County20.3-0.3 pts
33Delta County20.2-0.4 pts
34Larimer County20.1-0.2 pts
35Sedgwick County20-1.2 pts
36Denver County19.9-0.4 pts
37Boulder County19.7-0.2 pts
38Routt County19.7-0.2 pts
39San Miguel County19.6-0.9 pts
40La Plata County19.4-0.1 pts
41Archuleta County18.9+0.2 pts
42Logan County18.8-0 pts
43Dolores County18.7-0.9 pts
44Hinsdale County18.5-1.1 pts
45Las Animas County18.4-0.1 pts
46Costilla County18.3-1.3 pts
47Gunnison County17.5-0.3 pts
48Teller County17.5-0.5 pts
49Grand County17.4-0.8 pts
50Gilpin County17.1-0.2 pts
51Summit County17+0.1 pts
52Pitkin County16.9+0.3 pts
53Jackson County16.3-0.2 pts
54Fremont County16.2-0.1 pts
55Clear Creek County16.1-0.2 pts
56Park County16-0.7 pts
57Huerfano County16-0.3 pts
58Bent County15.7+0.4 pts
59Ouray County15.7-0.3 pts
60Custer County15.5+0.5 pts
61Chaffee County15.4-0.2 pts
62Mineral County13.3-0.8 pts
63San Juan County13.3-0.8 pts
64Crowley County11.2-1.7 pts

Other periods

About this ranking

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.

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 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 (Counties in Colorado by population under 18, 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 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, Counties in Colorado by population under 18, 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-under-18/colorado-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 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. Counties in Colorado by population under 18, 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-under-18/colorado-counties?period=2017.

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, Counties in Colorado by population under 18, 2017 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-under-18/colorado-counties?period=2017 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_colorado_by_2017,
  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: Counties in Colorado by population under 18, 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-under-18/colorado-counties?period=2017. 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: Counties in Colorado by population under 18, 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-under-18/colorado-counties?period=2017
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/colorado-counties?period=2017.
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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Rank Counties in Colorado by population under 18 using official data, and cite the source.
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Questions

Which county has the highest population under 18?

Conejos County, with 27.5% in 2017, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Crowley County, with 11.2% 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 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 2026-10-12.

Population under 18: other rankings

Counties in Colorado: more rankings