Counties in California by school enrolment, children aged 3 and 4

Mono County had the highest school enrolment, children aged 3 and 4 of 57 counties in 2021, at 93.5%. Trinity County had the lowest, at 4.4%. The median was 43% and the figure for California was 45.6%. Source: the U.S. Census Bureau.

Keep it in a collection in your library.
Highest93.5Mono County
Median4357 counties
California45.6History

Map of counties, 2021

Alameda County: 55.7 %Alpine County: 87.2 %Amador County: 43.9 %Butte County: 42.6 %Calaveras County: 44.8 %Colusa County: 51.5 %Contra Costa County: 51.9 %Del Norte County: 37.1 %El Dorado County: 59.1 %Fresno County: 37.1 %Glenn County: 17.9 %Humboldt County: 45.2 %Imperial County: 42 %Inyo County: 57.2 %Kern County: 31.4 %Kings County: 30.1 %Lake County: 42.4 %Lassen County: 37.4 %Los Angeles County: 49.9 %Madera County: 38.2 %Marin County: 64 %Mariposa County: 27.7 %Mendocino County: 47.1 %Merced County: 39 %Modoc County: 51.9 %Mono County: 93.5 %Monterey County: 35.7 %Napa County: 47.6 %Nevada County: 60.3 %Orange County: 53.7 %Placer County: 49.5 %Plumas County: 28 %Riverside County: 31 %Sacramento County: 40.3 %San Benito County: 32.8 %San Bernardino County: 33.3 %San Diego County: 47.1 %San Francisco County: 73.9 %San Joaquin County: 37.8 %San Luis Obispo County: 49.3 %San Mateo County: 62.2 %Santa Barbara County: 42.1 %Santa Clara County: 56.7 %Santa Cruz County: 45.1 %Shasta County: 41.8 %Siskiyou County: 40.9 %Solano County: 39.6 %Sonoma County: 47.4 %Stanislaus County: 36.6 %Sutter County: 41.1 %Tehama County: 48.3 %Trinity County: 4.4 %Tulare County: 31.2 %Tuolumne County: 60.8 %Ventura County: 43 %Yolo County: 51.6 %Yuba County: 40.2 %
  • Under 34
  • 34 to 40
  • 40 to 43
  • 43 to 49
  • 49 to 56
  • 56 and over
  • No data
%, 2021. Hatched areas have no value for this period. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2021

Mono County: 93.5 %Mono County93.5Alpine County: 87.2 %Alpine County87.2San Francisco County: 73.9 %San Francisco County73.9Marin County: 64 %Marin County64San Mateo County: 62.2 %San Mateo County62.2Tuolumne County: 60.8 %Tuolumne County60.8Nevada County: 60.3 %Nevada County60.3El Dorado County: 59.1 %El Dorado County59.1Inyo County: 57.2 %Inyo County57.2Santa Clara County: 56.7 %Santa Clara County56.7Alameda County: 55.7 %Alameda County55.7Orange County: 53.7 %Orange County53.7Modoc County: 51.9 %Modoc County51.9Contra Costa County: 51.9 %Contra Costa County51.9Yolo County: 51.6 %Yolo County51.6Colusa County: 51.5 %Colusa County51.5Los Angeles County: 49.9 %Los Angeles County49.9Placer County: 49.5 %Placer County49.5San Luis Obispo County: 49.3 %San Luis Obispo County49.3Tehama County: 48.3 %Tehama County48.3Napa County: 47.6 %Napa County47.6Sonoma County: 47.4 %Sonoma County47.4San Diego County: 47.1 %San Diego County47.1Mendocino County: 47.1 %Mendocino County47.1Humboldt County: 45.2 %Humboldt County45.2Santa Cruz County: 45.1 %Santa Cruz County45.1Calaveras County: 44.8 %Calaveras County44.8Amador County: 43.9 %Amador County43.9Ventura County: 43 %Ventura County43Butte County: 42.6 %Butte County42.6Lake County: 42.4 %Lake County42.4Santa Barbara County: 42.1 %Santa Barbara County42.1Imperial County: 42 %Imperial County42Shasta County: 41.8 %Shasta County41.8Sutter County: 41.1 %Sutter County41.1Siskiyou County: 40.9 %Siskiyou County40.9Sacramento County: 40.3 %Sacramento County40.3Yuba County: 40.2 %Yuba County40.2Solano County: 39.6 %Solano County39.6Merced County: 39 %Merced County39Madera County: 38.2 %Madera County38.2San Joaquin County: 37.8 %San Joaquin County37.8Lassen County: 37.4 %Lassen County37.4Del Norte County: 37.1 %Del Norte County37.1Fresno County: 37.1 %Fresno County37.1Stanislaus County: 36.6 %Stanislaus County36.6Monterey County: 35.7 %Monterey County35.7San Bernardino County: 33.3 %San Bernardino County33.3San Benito County: 32.8 %San Benito County32.8Kern County: 31.4 %Kern County31.4Tulare County: 31.2 %Tulare County31.2Riverside County: 31 %Riverside County31Kings County: 30.1 %Kings County30.1Plumas County: 28 %Plumas County28Mariposa County: 27.7 %Mariposa County27.7Glenn County: 17.9 %Glenn County17.9Trinity County: 4.4 %Trinity County4.4Mono County: 93.5 %Mono County93.5Alpine County: 87.2 %Alpine County87.2San Francisco County: 73.9 %San Francisco County73.9Marin County: 64 %Marin County64San Mateo County: 62.2 %San Mateo County62.2Tuolumne County: 60.8 %Tuolumne County60.8Nevada County: 60.3 %Nevada County60.3El Dorado County: 59.1 %El Dorado County59.1Inyo County: 57.2 %Inyo County57.2Santa Clara County: 56.7 %Santa Clara County56.7Alameda County: 55.7 %Alameda County55.7Orange County: 53.7 %Orange County53.7Modoc County: 51.9 %Modoc County51.9Contra Costa County: 51.9 %Contra Costa County51.9Yolo County: 51.6 %Yolo County51.6Colusa County: 51.5 %Colusa County51.5Los Angeles County: 49.9 %Los Angeles County49.9Placer County: 49.5 %Placer County49.5San Luis Obispo County: 49.3 %San Luis Obispo County49.3Tehama County: 48.3 %Tehama County48.3Napa County: 47.6 %Napa County47.6Sonoma County: 47.4 %Sonoma County47.4San Diego County: 47.1 %San Diego County47.1Mendocino County: 47.1 %Mendocino County47.1Humboldt County: 45.2 %Humboldt County45.2Santa Cruz County: 45.1 %Santa Cruz County45.1Calaveras County: 44.8 %Calaveras County44.8Amador County: 43.9 %Amador County43.9Ventura County: 43 %Ventura County43Butte County: 42.6 %Butte County42.6Lake County: 42.4 %Lake County42.4Santa Barbara County: 42.1 %Santa Barbara County42.1Imperial County: 42 %Imperial County42Shasta County: 41.8 %Shasta County41.8Sutter County: 41.1 %Sutter County41.1Siskiyou County: 40.9 %Siskiyou County40.9Sacramento County: 40.3 %Sacramento County40.3Yuba County: 40.2 %Yuba County40.2Solano County: 39.6 %Solano County39.6Merced County: 39 %Merced County39Madera County: 38.2 %Madera County38.2San Joaquin County: 37.8 %San Joaquin County37.8Lassen County: 37.4 %Lassen County37.4Del Norte County: 37.1 %Del Norte County37.1Fresno County: 37.1 %Fresno County37.1Stanislaus County: 36.6 %Stanislaus County36.6Monterey County: 35.7 %Monterey County35.7San Bernardino County: 33.3 %San Bernardino County33.3San Benito County: 32.8 %San Benito County32.8Kern County: 31.4 %Kern County31.4Tulare County: 31.2 %Tulare County31.2Riverside County: 31 %Riverside County31Kings County: 30.1 %Kings County30.1Plumas County: 28 %Plumas County28Mariposa County: 27.7 %Mariposa County27.7Glenn County: 17.9 %Glenn County17.9Trinity County: 4.4 %Trinity County4.4
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

Other periods

About this ranking

Children aged 3 and 4 enrolled in public or private school, including nursery school and preschool, at any time in the three months before the interview, as a percentage of all children aged 3 and 4. United States: American Community Survey five-year estimate, where the period shown is the last year of the five-year span.

Reported by households, so it includes private nursery schools. Small counties have only a few dozen children in the sample, and their rates can swing widely between periods.

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. American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b14003.dat. 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). American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs (Counties in California by school enrolment, children aged 3 and 4, 2021) [Data set]. Retrieved October 12, 2026, from https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b14003.dat

MLA 9

American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs, Counties in California by school enrolment, children aged 3 and 4, 2021. U.S. Census Bureau, 29 Jan. 2026, https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b14003.dat. Invokely, https://invokely.ai/rankings/preschool-enrollment-ages-3-4/california-counties?period=2021. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs. Counties in California by school enrolment, children aged 3 and 4, 2021. Dataset. Accessed October 12, 2026. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b14003.dat. Also distributed by Invokely, https://invokely.ai/rankings/preschool-enrollment-ages-3-4/california-counties?period=2021.

Harvard

U.S. Census Bureau (2026) American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs, Counties in California by school enrolment, children aged 3 and 4, 2021 [Dataset]. Available at: https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b14003.dat, via Invokely: https://invokely.ai/rankings/preschool-enrollment-ages-3-4/california-counties?period=2021 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_california_by_2021,
  author = {{U.S. Census Bureau}},
  title = {{American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs: Counties in California by school enrolment, children aged 3 and 4, 2021}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b14003.dat},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/preschool-enrollment-ages-3-4/california-counties?period=2021. Publisher attribution: U.S. Census Bureau. American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary\_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b14003.dat. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs: Counties in California by school enrolment, children aged 3 and 4, 2021
PY  - 2026
DA  - 2026/01/29
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b14003.dat
L2  - https://invokely.ai/rankings/preschool-enrollment-ages-3-4/california-counties?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/preschool-enrollment-ages-3-4/california-counties?period=2021.
N1  - Publisher attribution: U.S. Census Bureau. American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b14003.dat. Retrieved 2026-10-12.
ER  - 
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Rank Counties in California by school enrolment, children aged 3 and 4 using official data, and cite the source.
rank_places {"indicator":"preschool_enrolment_rate_3_4","level":"province","within":"California","limit":10}
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Questions

Which county has the highest school enrolment, children aged 3 and 4?

Mono County, with 93.5% in 2021, according to the U.S. Census Bureau.

Which county has the lowest school enrolment, children aged 3 and 4?

Trinity County, with 4.4% in 2021.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, American Community Survey 5-year estimates, table B14003: children aged 3 and 4 enrolled in public or private school as a percentage of all children aged 3 and 4, calculated with stored inputs. Retrieved 2026-10-12.

School enrolment, children aged 3 and 4: other rankings

Counties in California: more rankings