Counties in California by population under 18

Tulare County had the highest population under 18 of 58 counties in 2016, at 31.1%. San Francisco County had the lowest, at 13.1%. The median was 21.5% and the figure for California was 23%. Source: the U.S. Census Bureau.

Keep it in a collection in your library.
Highest31.1Tulare County
Median21.558 counties
California23History

Map of counties, 2016

Alameda County: 21.1 %Alpine County: 16.9 %Amador County: 16 %Butte County: 20.3 %Calaveras County: 17.5 %Colusa County: 28.2 %Contra Costa County: 23.3 %Del Norte County: 21 %El Dorado County: 20.8 %Fresno County: 28.4 %Glenn County: 26.1 %Humboldt County: 19.8 %Imperial County: 27.6 %Inyo County: 20.4 %Kern County: 29 %Kings County: 27 %Lake County: 20.2 %Lassen County: 16.7 %Los Angeles County: 21.9 %Madera County: 27.8 %Marin County: 20.8 %Mariposa County: 16.9 %Mendocino County: 21.3 %Merced County: 29.7 %Modoc County: 20.4 %Mono County: 20.1 %Monterey County: 26.1 %Napa County: 21.2 %Nevada County: 17.8 %Orange County: 22.1 %Placer County: 23 %Plumas County: 17 %Riverside County: 25.8 %Sacramento County: 24 %San Benito County: 26 %San Bernardino County: 26.5 %San Diego County: 21.8 %San Francisco County: 13.1 %San Joaquin County: 27.3 %San Luis Obispo County: 18.3 %San Mateo County: 21.1 %Santa Barbara County: 22.3 %Santa Clara County: 22.3 %Santa Cruz County: 19.7 %Shasta County: 21.4 %Sierra County: 15.8 %Siskiyou County: 19.8 %Solano County: 22.5 %Sonoma County: 20.3 %Stanislaus County: 26.9 %Sutter County: 26.1 %Tehama County: 24.2 %Trinity County: 16.4 %Tulare County: 31.1 %Tuolumne County: 16.5 %Ventura County: 23.5 %Yolo County: 21.7 %Yuba County: 27 %
  • Under 18
  • 18 to 20
  • 20 to 22
  • 22 to 24
  • 24 to 27
  • 27 and over
%, 2016. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2016

Tulare County: 31.1 %Tulare County31.1Merced County: 29.7 %Merced County29.7Kern County: 29 %Kern County29Fresno County: 28.4 %Fresno County28.4Colusa County: 28.2 %Colusa County28.2Madera County: 27.8 %Madera County27.8Imperial County: 27.6 %Imperial County27.6San Joaquin County: 27.3 %San Joaquin County27.3Yuba County: 27 %Yuba County27Kings County: 27 %Kings County27Stanislaus County: 26.9 %Stanislaus County26.9San Bernardino County: 26.5 %San Bernardino County26.5Sutter County: 26.1 %Sutter County26.1Monterey County: 26.1 %Monterey County26.1Glenn County: 26.1 %Glenn County26.1San Benito County: 26 %San Benito County26Riverside County: 25.8 %Riverside County25.8Tehama County: 24.2 %Tehama County24.2Sacramento County: 24 %Sacramento County24Ventura County: 23.5 %Ventura County23.5Contra Costa County: 23.3 %Contra Costa County23.3Placer County: 23 %Placer County23Solano County: 22.5 %Solano County22.5Santa Clara County: 22.3 %Santa Clara County22.3Santa Barbara County: 22.3 %Santa Barbara County22.3Orange County: 22.1 %Orange County22.1Los Angeles County: 21.9 %Los Angeles County21.9San Diego County: 21.8 %San Diego County21.8Yolo County: 21.7 %Yolo County21.7Shasta County: 21.4 %Shasta County21.4Mendocino County: 21.3 %Mendocino County21.3Napa County: 21.2 %Napa County21.2San Mateo County: 21.1 %San Mateo County21.1Alameda County: 21.1 %Alameda County21.1Del Norte County: 21 %Del Norte County21Marin County: 20.8 %Marin County20.8El Dorado County: 20.8 %El Dorado County20.8Inyo County: 20.4 %Inyo County20.4Modoc County: 20.4 %Modoc County20.4Sonoma County: 20.3 %Sonoma County20.3Butte County: 20.3 %Butte County20.3Lake County: 20.2 %Lake County20.2Mono County: 20.1 %Mono County20.1Humboldt County: 19.8 %Humboldt County19.8Siskiyou County: 19.8 %Siskiyou County19.8Santa Cruz County: 19.7 %Santa Cruz County19.7San Luis Obispo County: 18.3 %San Luis Obispo County18.3Nevada County: 17.8 %Nevada County17.8Calaveras County: 17.5 %Calaveras County17.5Plumas County: 17 %Plumas County17Alpine County: 16.9 %Alpine County16.9Mariposa County: 16.9 %Mariposa County16.9Lassen County: 16.7 %Lassen County16.7Tuolumne County: 16.5 %Tuolumne County16.5Trinity County: 16.4 %Trinity County16.4Amador County: 16 %Amador County16Sierra County: 15.8 %Sierra County15.8San Francisco County: 13.1 %San Francisco County13.1Tulare County: 31.1 %Tulare County31.1Merced County: 29.7 %Merced County29.7Kern County: 29 %Kern County29Fresno County: 28.4 %Fresno County28.4Colusa County: 28.2 %Colusa County28.2Madera County: 27.8 %Madera County27.8Imperial County: 27.6 %Imperial County27.6San Joaquin County: 27.3 %San Joaquin County27.3Yuba County: 27 %Yuba County27Kings County: 27 %Kings County27Stanislaus County: 26.9 %Stanislaus County26.9San Bernardino County: 26.5 %San Bernardino County26.5Sutter County: 26.1 %Sutter County26.1Monterey County: 26.1 %Monterey County26.1Glenn County: 26.1 %Glenn County26.1San Benito County: 26 %San Benito County26Riverside County: 25.8 %Riverside County25.8Tehama County: 24.2 %Tehama County24.2Sacramento County: 24 %Sacramento County24Ventura County: 23.5 %Ventura County23.5Contra Costa County: 23.3 %Contra Costa County23.3Placer County: 23 %Placer County23Solano County: 22.5 %Solano County22.5Santa Clara County: 22.3 %Santa Clara County22.3Santa Barbara County: 22.3 %Santa Barbara County22.3Orange County: 22.1 %Orange County22.1Los Angeles County: 21.9 %Los Angeles County21.9San Diego County: 21.8 %San Diego County21.8Yolo County: 21.7 %Yolo County21.7Shasta County: 21.4 %Shasta County21.4Mendocino County: 21.3 %Mendocino County21.3Napa County: 21.2 %Napa County21.2San Mateo County: 21.1 %San Mateo County21.1Alameda County: 21.1 %Alameda County21.1Del Norte County: 21 %Del Norte County21Marin County: 20.8 %Marin County20.8El Dorado County: 20.8 %El Dorado County20.8Inyo County: 20.4 %Inyo County20.4Modoc County: 20.4 %Modoc County20.4Sonoma County: 20.3 %Sonoma County20.3Butte County: 20.3 %Butte County20.3Lake County: 20.2 %Lake County20.2Mono County: 20.1 %Mono County20.1Humboldt County: 19.8 %Humboldt County19.8Siskiyou County: 19.8 %Siskiyou County19.8Santa Cruz County: 19.7 %Santa Cruz County19.7San Luis Obispo County: 18.3 %San Luis Obispo County18.3Nevada County: 17.8 %Nevada County17.8Calaveras County: 17.5 %Calaveras County17.5Plumas County: 17 %Plumas County17Alpine County: 16.9 %Alpine County16.9Mariposa County: 16.9 %Mariposa County16.9Lassen County: 16.7 %Lassen County16.7Tuolumne County: 16.5 %Tuolumne County16.5Trinity County: 16.4 %Trinity County16.4Amador County: 16 %Amador County16Sierra County: 15.8 %Sierra County15.8San Francisco County: 13.1 %San Francisco County13.1
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2016 (%)Change on 2015
1Tulare County31.1-0.2 pts
2Merced County29.7-0.1 pts
3Kern County29-0.2 pts
4Fresno County28.4-0.1 pts
5Colusa County28.2+0.1 pts
6Madera County27.8-0 pts
7Imperial County27.6-0.1 pts
8San Joaquin County27.3-0.2 pts
9Yuba County27-0.4 pts
10Kings County27-0.2 pts
11Stanislaus County26.9-0.1 pts
12San Bernardino County26.5-0.3 pts
13Sutter County26.1+0.1 pts
14Monterey County26.1-0.2 pts
15Glenn County26.1-0.3 pts
16San Benito County26-0.4 pts
17Riverside County25.8-0.3 pts
18Tehama County24.2+0.1 pts
19Sacramento County24-0.2 pts
20Ventura County23.5-0.3 pts
21Contra Costa County23.3-0.2 pts
22Placer County23-0.1 pts
23Solano County22.5-0.2 pts
24Santa Clara County22.3-0.3 pts
25Santa Barbara County22.3-0.1 pts
26Orange County22.1-0.3 pts
27Los Angeles County21.9-0.4 pts
28San Diego County21.8-0.2 pts
29Yolo County21.7-0.1 pts
30Shasta County21.4-0 pts
31Mendocino County21.3-0.1 pts
32Napa County21.2-0.3 pts
33San Mateo County21.1-0.3 pts
34Alameda County21.1-0.2 pts
35Del Norte County21+0.3 pts
36Marin County20.80 pts
37El Dorado County20.8-0.2 pts
38Inyo County20.4+0.1 pts
39Modoc County20.4+0.3 pts
40Sonoma County20.3-0.2 pts
41Butte County20.3-0.1 pts
42Lake County20.2+0.1 pts
43Mono County20.1+0.1 pts
44Humboldt County19.80 pts
45Siskiyou County19.80 pts
46Santa Cruz County19.7-0.2 pts
47San Luis Obispo County18.3-0.1 pts
48Nevada County17.8-0.2 pts
49Calaveras County17.5-0.2 pts
50Plumas County17+0.3 pts
51Alpine County16.9-0.6 pts
52Mariposa County16.9+0.3 pts
53Lassen County16.7+0.2 pts
54Tuolumne County16.5-0.1 pts
55Trinity County16.4-0.1 pts
56Amador County16+0.3 pts
57Sierra County15.8-0.4 pts
58San Francisco County13.1-0 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 California by population under 18, 2016) [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 California by population under 18, 2016. 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/california-counties?period=2016. 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 California by population under 18, 2016. 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/california-counties?period=2016.

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 California by population under 18, 2016 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-under-18/california-counties?period=2016 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_california_by_2016,
  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 California by population under 18, 2016}},
  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/california-counties?period=2016. 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 California by population under 18, 2016
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/california-counties?period=2016
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/california-counties?period=2016.
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 California by population under 18 using official data, and cite the source.
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Questions

Which county has the highest population under 18?

Tulare County, with 31.1% in 2016, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

San Francisco County, with 13.1% in 2016.

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 California: more rankings