Data / Rankings / Population under 18 / Counties in Colorado

Counties in Colorado by population under 18

Weld County had the highest population under 18 of 64 counties in 2019, at 26.6%. Crowley County had the lowest, at 10.4%. The median was 19.9% and the figure for Colorado was 22.1%. Source: the U.S. Census Bureau.

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Highest26.6Weld County
Lowest10.4Crowley County
Median19.964 counties
Colorado22.1History

Map of counties, 2019

Adams County: 26.1 %Alamosa County: 23.4 %Arapahoe County: 23.6 %Archuleta County: 18.4 %Baca County: 21.6 %Bent County: 16 %Boulder County: 19.2 %Broomfield County: 22.2 %Chaffee County: 15.4 %Cheyenne County: 23.9 %Clear Creek County: 15.3 %Conejos County: 26.4 %Costilla County: 18.3 %Crowley County: 10.4 %Custer County: 14.8 %Delta County: 19.8 %Denver County: 19 %Dolores County: 18.6 %Douglas County: 26.1 %Eagle County: 22.5 %Elbert County: 21.8 %El Paso County: 23.7 %Fremont County: 15.8 %Garfield County: 25.1 %Gilpin County: 15.9 %Grand County: 17.1 %Gunnison County: 17.2 %Hinsdale County: 17.1 %Huerfano County: 15.9 %Jackson County: 16.2 %Jefferson County: 19.7 %Kiowa County: 24.3 %Kit Carson County: 25 %Lake County: 20.8 %La Plata County: 18.9 %Larimer County: 19.7 %Las Animas County: 17.3 %Lincoln County: 20.7 %Logan County: 18.7 %Mesa County: 21.2 %Mineral County: 13.5 %Moffat County: 24.7 %Montezuma County: 21.1 %Montrose County: 21.4 %Morgan County: 26.5 %Otero County: 23.7 %Ouray County: 14.7 %Park County: 15.9 %Phillips County: 24.5 %Pitkin County: 16.7 %Prowers County: 25 %Pueblo County: 22.2 %Rio Blanco County: 25 %Rio Grande County: 22.6 %Routt County: 19.4 %Saguache County: 21 %San Juan County: 15.4 %San Miguel County: 19.5 %Sedgwick County: 20 %Summit County: 16.8 %Teller County: 16.9 %Washington County: 22.5 %Weld County: 26.6 %Yuma County: 26.5 %
  • Under 16
  • 16 to 18
  • 18 to 20
  • 20 to 22
  • 22 to 25
  • 25 and over
%, 2019. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2019

Weld County: 26.6 %Weld County26.6Yuma County: 26.5 %Yuma County26.5Morgan County: 26.5 %Morgan County26.5Conejos County: 26.4 %Conejos County26.4Douglas County: 26.1 %Douglas County26.1Adams County: 26.1 %Adams County26.1Garfield County: 25.1 %Garfield County25.1Prowers County: 25 %Prowers County25Rio Blanco County: 25 %Rio Blanco County25Kit Carson County: 25 %Kit Carson County25Moffat County: 24.7 %Moffat County24.7Phillips County: 24.5 %Phillips County24.5Kiowa County: 24.3 %Kiowa County24.3Cheyenne County: 23.9 %Cheyenne County23.9El Paso County: 23.7 %El Paso County23.7Otero County: 23.7 %Otero County23.7Arapahoe County: 23.6 %Arapahoe County23.6Alamosa County: 23.4 %Alamosa County23.4Rio Grande County: 22.6 %Rio Grande County22.6Eagle County: 22.5 %Eagle County22.5Washington County: 22.5 %Washington County22.5Broomfield County: 22.2 %Broomfield County22.2Pueblo County: 22.2 %Pueblo County22.2Elbert County: 21.8 %Elbert County21.8Baca County: 21.6 %Baca County21.6Montrose County: 21.4 %Montrose County21.4Mesa County: 21.2 %Mesa County21.2Montezuma County: 21.1 %Montezuma County21.1Saguache County: 21 %Saguache County21Lake County: 20.8 %Lake County20.8Lincoln County: 20.7 %Lincoln County20.7Sedgwick County: 20 %Sedgwick County20Delta County: 19.8 %Delta County19.8Jefferson County: 19.7 %Jefferson County19.7Larimer County: 19.7 %Larimer County19.7San Miguel County: 19.5 %San Miguel County19.5Routt County: 19.4 %Routt County19.4Boulder County: 19.2 %Boulder County19.2Denver County: 19 %Denver County19La Plata County: 18.9 %La Plata County18.9Weld County: 26.6 %Weld County26.6Yuma County: 26.5 %Yuma County26.5Morgan County: 26.5 %Morgan County26.5Conejos County: 26.4 %Conejos County26.4Douglas County: 26.1 %Douglas County26.1Adams County: 26.1 %Adams County26.1Garfield County: 25.1 %Garfield County25.1Prowers County: 25 %Prowers County25Rio Blanco County: 25 %Rio Blanco County25Kit Carson County: 25 %Kit Carson County25Moffat County: 24.7 %Moffat County24.7Phillips County: 24.5 %Phillips County24.5Kiowa County: 24.3 %Kiowa County24.3Cheyenne County: 23.9 %Cheyenne County23.9El Paso County: 23.7 %El Paso County23.7Otero County: 23.7 %Otero County23.7Arapahoe County: 23.6 %Arapahoe County23.6Alamosa County: 23.4 %Alamosa County23.4Rio Grande County: 22.6 %Rio Grande County22.6Eagle County: 22.5 %Eagle County22.5Washington County: 22.5 %Washington County22.5Broomfield County: 22.2 %Broomfield County22.2Pueblo County: 22.2 %Pueblo County22.2Elbert County: 21.8 %Elbert County21.8Baca County: 21.6 %Baca County21.6Montrose County: 21.4 %Montrose County21.4Mesa County: 21.2 %Mesa County21.2Montezuma County: 21.1 %Montezuma County21.1Saguache County: 21 %Saguache County21Lake County: 20.8 %Lake County20.8Lincoln County: 20.7 %Lincoln County20.7Sedgwick County: 20 %Sedgwick County20Delta County: 19.8 %Delta County19.8Jefferson County: 19.7 %Jefferson County19.7Larimer County: 19.7 %Larimer County19.7San Miguel County: 19.5 %San Miguel County19.5Routt County: 19.4 %Routt County19.4Boulder County: 19.2 %Boulder County19.2Denver County: 19 %Denver County19La Plata County: 18.9 %La Plata County18.9
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2019 (%)Change on 2018
1Weld County26.6-0.2 pts
2Yuma County26.50 pts
3Morgan County26.5-0.1 pts
4Conejos County26.4-0.7 pts
5Douglas County26.1-0.7 pts
6Adams County26.1-0.5 pts
7Garfield County25.1-0.2 pts
8Prowers County25-0.3 pts
9Rio Blanco County25+0.1 pts
10Kit Carson County25-0.2 pts
11Moffat County24.7-0.8 pts
12Phillips County24.5-0.2 pts
13Kiowa County24.3+1.2 pts
14Cheyenne County23.9-0.4 pts
15El Paso County23.7-0.4 pts
16Otero County23.7-0 pts
17Arapahoe County23.6-0.2 pts
18Alamosa County23.4-0.6 pts
19Rio Grande County22.6-0.3 pts
20Eagle County22.5-0.2 pts
21Washington County22.5-0.2 pts
22Broomfield County22.2-0.8 pts
23Pueblo County22.2-0.2 pts
24Elbert County21.8-0.3 pts
25Baca County21.6-0.3 pts
26Montrose County21.4-0.4 pts
27Mesa County21.2-0.4 pts
28Montezuma County21.1-0.5 pts
29Saguache County21-0.3 pts
30Lake County20.8-0 pts
31Lincoln County20.7+0.3 pts
32Sedgwick County20-0.2 pts
33Delta County19.8-0.4 pts
34Jefferson County19.7-0.3 pts
35Larimer County19.7-0.3 pts
36San Miguel County19.5-0.1 pts
37Routt County19.4-0.2 pts
38Boulder County19.2-0.3 pts
39Denver County19-0.5 pts
40La Plata County18.9-0.3 pts
41Logan County18.7+0.1 pts
42Dolores County18.6-0.4 pts
43Archuleta County18.4-0.3 pts
44Costilla County18.3+0.1 pts
45Las Animas County17.3-0.9 pts
46Gunnison County17.2-0.3 pts
47Hinsdale County17.1-0.9 pts
48Grand County17.1+0.1 pts
49Teller County16.9-0.1 pts
50Summit County16.8-0.2 pts
51Pitkin County16.7-0.1 pts
52Jackson County16.20 pts
53Bent County16+0.5 pts
54Huerfano County15.9-0.4 pts
55Park County15.9+0.1 pts
56Gilpin County15.9-0.6 pts
57Fremont County15.8-0.2 pts
58Chaffee County15.4-0 pts
59San Juan County15.4+1.4 pts
60Clear Creek County15.3-0.2 pts
61Custer County14.80 pts
62Ouray County14.7-0.3 pts
63Mineral County13.5-1.3 pts
64Crowley County10.4-0.5 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, 2019) [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, 2019. 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=2019. 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, 2019. 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=2019.

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, 2019 [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=2019 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_colorado_by_2019,
  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, 2019}},
  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=2019. 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, 2019
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=2019
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/colorado-counties?period=2019.
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?

Weld County, with 26.6% in 2019, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Crowley County, with 10.4% in 2019.

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