Data / Rankings / Population aged 18 to 64 / Counties in California

Counties in California by population aged 18 to 64

San Francisco County had the highest population aged 18 to 64 of 58 counties in 2024, at 68.1%. Plumas County had the lowest, at 50.2%. The median was 58.9% and the figure for California was 61.8%. Source: the U.S. Census Bureau.

Highest68.1San Francisco County
Lowest50.2Plumas County
Median58.958 counties
California61.8History

All counties, 2024

San Francisco County: 68.1 %San Francisco County68.1Yolo County: 65.6 %Yolo County65.6Santa Clara County: 65 %Santa Clara County65Alameda County: 64.1 %Alameda County64.1Los Angeles County: 64 %Los Angeles County64Lassen County: 63 %Lassen County63San Diego County: 62.8 %San Diego County62.8Orange County: 62.3 %Orange County62.3San Mateo County: 62.3 %San Mateo County62.3Kings County: 62.2 %Kings County62.2Mono County: 61.6 %Mono County61.6San Bernardino County: 61.4 %San Bernardino County61.4Santa Cruz County: 61.2 %Santa Cruz County61.2Sacramento County: 61 %Sacramento County61San Benito County: 60.6 %San Benito County60.6Solano County: 60.1 %Solano County60.1San Joaquin County: 60.1 %San Joaquin County60.1Contra Costa County: 60 %Contra Costa County60Merced County: 60 %Merced County60Humboldt County: 60 %Humboldt County60Riverside County: 59.9 %Riverside County59.9Ventura County: 59.8 %Ventura County59.8Monterey County: 59.8 %Monterey County59.8Santa Barbara County: 59.7 %Santa Barbara County59.7Kern County: 59.4 %Kern County59.4Yuba County: 59.2 %Yuba County59.2Stanislaus County: 59.2 %Stanislaus County59.2Butte County: 59.2 %Butte County59.2Fresno County: 59.1 %Fresno County59.1Imperial County: 58.7 %Imperial County58.7Sutter County: 58.6 %Sutter County58.6San Luis Obispo County: 58.4 %San Luis Obispo County58.4Napa County: 58.3 %Napa County58.3Tulare County: 58.2 %Tulare County58.2Del Norte County: 58.2 %Del Norte County58.2Madera County: 58.2 %Madera County58.2Sonoma County: 58.1 %Sonoma County58.1Colusa County: 56.9 %Colusa County56.9Alpine County: 56.9 %Alpine County56.9Glenn County: 56.7 %Glenn County56.7Placer County: 56.5 %Placer County56.5Marin County: 56.3 %Marin County56.3Trinity County: 55.4 %Trinity County55.4El Dorado County: 55.3 %El Dorado County55.3Shasta County: 55.2 %Shasta County55.2Inyo County: 54.8 %Inyo County54.8Tehama County: 54.6 %Tehama County54.6Mendocino County: 54.5 %Mendocino County54.5Lake County: 54.4 %Lake County54.4Amador County: 54.2 %Amador County54.2Tuolumne County: 53.6 %Tuolumne County53.6Nevada County: 53 %Nevada County53Calaveras County: 51.9 %Calaveras County51.9Mariposa County: 51.6 %Mariposa County51.6Sierra County: 51.5 %Sierra County51.5Siskiyou County: 51.3 %Siskiyou County51.3Modoc County: 50.3 %Modoc County50.3Plumas County: 50.2 %Plumas County50.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2024 (%)Change on 2023
1San Francisco County68.1-0.2 pts
2Yolo County65.60 pts
3Santa Clara County65+0.1 pts
4Alameda County64.1-0.2 pts
5Los Angeles County64-0.2 pts
6Lassen County63-0.4 pts
7San Diego County62.8-0.1 pts
8Orange County62.3-0.2 pts
9San Mateo County62.3-0 pts
10Kings County62.2-0.1 pts
11Mono County61.6-0.9 pts
12San Bernardino County61.4+0.1 pts
13Santa Cruz County61.2-0.4 pts
14Sacramento County61-0.1 pts
15San Benito County60.6-0.1 pts
16Solano County60.1-0.2 pts
17San Joaquin County60.1+0.2 pts
18Contra Costa County60-0.1 pts
19Merced County60+0.2 pts
20Humboldt County60-0.3 pts
21Riverside County59.90 pts
22Ventura County59.8-0.2 pts
23Monterey County59.8-0.1 pts
24Santa Barbara County59.7-0.3 pts
25Kern County59.4+0.1 pts
26Yuba County59.2-0 pts
27Stanislaus County59.2+0.1 pts
28Butte County59.2-0.3 pts
29Fresno County59.1+0.1 pts
30Imperial County58.7+0.1 pts
31Sutter County58.6-0 pts
32San Luis Obispo County58.4-0.4 pts
33Napa County58.3-0.3 pts
34Tulare County58.2+0.1 pts
35Del Norte County58.2+0.5 pts
36Madera County58.2+0.2 pts
37Sonoma County58.1-0.4 pts
38Colusa County56.9+0.3 pts
39Alpine County56.9-0.5 pts
40Glenn County56.7+0.2 pts
41Placer County56.5-0.1 pts
42Marin County56.3-0.2 pts
43Trinity County55.4-0.8 pts
44El Dorado County55.3-0.5 pts
45Shasta County55.2-0.2 pts
46Inyo County54.8-0.1 pts
47Tehama County54.6-0.3 pts
48Mendocino County54.5-0.3 pts
49Lake County54.4-0.3 pts
50Amador County54.2-0.3 pts
51Tuolumne County53.6-0.3 pts
52Nevada County53-0.3 pts
53Calaveras County51.9-0.6 pts
54Mariposa County51.60 pts
55Sierra County51.5-0.8 pts
56Siskiyou County51.3-0.5 pts
57Modoc County50.3-0.3 pts
58Plumas County50.2-0.4 pts

Other periods

About this ranking

Residents aged 18 to 64 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.

Not comparable with working-age shares for ages 15 to 64 used in EU and World Bank statistics.

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 18 to 64 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 18 to 64 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 aged 18 to 64, 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: residents aged 18 to 64 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 aged 18 to 64, 2024. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/population-18-64/california-counties?period=2024. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 18 to 64 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 aged 18 to 64, 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/population-18-64/california-counties?period=2024.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 18 to 64 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 aged 18 to 64, 2024 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-18-64/california-counties?period=2024 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_california_by_2024,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: residents aged 18 to 64 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 aged 18 to 64, 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/population-18-64/california-counties?period=2024. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 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 18 to 64 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 aged 18 to 64, 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/population-18-64/california-counties?period=2024
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/california-counties?period=2024.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 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

Which county has the highest population aged 18 to 64?

San Francisco County, with 68.1% in 2024, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Plumas County, with 50.2% 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: residents aged 18 to 64 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 aged 18 to 64: other rankings

Counties in California: more rankings