Counties in California by uninsured rate, all ages (US)
Sierra County had the highest uninsured rate, all ages (US) of 58 counties in 2021, at 15.5%. Placer County had the lowest, at 3.4%. The median was 6.6% and the figure for California was 7.2%. Source: the U.S. Census Bureau.
Map of counties, 2021
- Under 4.7
- 4.7 to 6
- 6 to 6.6
- 6.6 to 7.5
- 7.5 to 8.6
- 8.6 and over
All counties, 2021
Full ranking
Other periods
About this ranking
People without health insurance coverage of any kind, as a percentage of the civilian noninstitutionalized population. United States: American Community Survey five-year estimate, where the period shown is the last year of the five-year span.
Coverage is what people reported at the interview, so the five-year figure averages five years of answers. People whose only coverage is the Indian Health Service count as uninsured. Active-duty military and people living in institutions are outside the universe. For single-year model-based county figures under 65, see uninsured_rate_under_65, uninsured_rate_18_64 and uninsured_rate_under_19 (SAHIE), a different source.
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 B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b27010.dat. Retrieved 2026-10-12.Citation styles
APA 7
U.S. Census Bureau. (2026). American Community Survey 5-year estimates, table B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs (Counties in California by uninsured rate, all ages (US), 2021) [Data set]. Retrieved October 12, 2026, from https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b27010.dat
MLA 9
American Community Survey 5-year estimates, table B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs, Counties in California by uninsured rate, all ages (US), 2021. U.S. Census Bureau, 29 Jan. 2026, https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b27010.dat. Invokely, https://invokely.ai/rankings/uninsured-rate/california-counties?period=2021. Accessed 12 Oct. 2026.
Chicago (author-date)
U.S. Census Bureau. 2026. American Community Survey 5-year estimates, table B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs. Counties in California by uninsured rate, all ages (US), 2021. Dataset. Accessed October 12, 2026. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b27010.dat. Also distributed by Invokely, https://invokely.ai/rankings/uninsured-rate/california-counties?period=2021.
Harvard
U.S. Census Bureau (2026) American Community Survey 5-year estimates, table B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs, Counties in California by uninsured rate, all ages (US), 2021 [Dataset]. Available at: https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b27010.dat, via Invokely: https://invokely.ai/rankings/uninsured-rate/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 B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs: Counties in California by uninsured rate, all ages (US), 2021}},
year = {2026},
howpublished = {Data set},
url = {https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b27010.dat},
urldate = {2026-10-12},
note = {Accessed via Invokely, https://invokely.ai/rankings/uninsured-rate/california-counties?period=2021. Publisher attribution: U.S. Census Bureau. American Community Survey 5-year estimates, table B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary\_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b27010.dat. Retrieved 2026-10-12.},
}
RIS
TY - DATA
AU - U.S. Census Bureau
TI - American Community Survey 5-year estimates, table B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs: Counties in California by uninsured rate, all ages (US), 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-b27010.dat
L2 - https://invokely.ai/rankings/uninsured-rate/california-counties?period=2021
Y2 - 2026/10/12
N1 - Accessed via Invokely, https://invokely.ai/rankings/uninsured-rate/california-counties?period=2021.
N1 - Publisher attribution: U.S. Census Bureau. American Community Survey 5-year estimates, table B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b27010.dat. Retrieved 2026-10-12.
ER -
Use this data in your AI agent
Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:
Rank Counties in California by uninsured rate, all ages (US) using official data, and cite the source.
rank_places {"indicator":"uninsured_rate","level":"province","within":"California","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=uninsured_rate&level=province&within=California&limit=10Questions
Which county has the highest uninsured rate, all ages (US)?
Sierra County, with 15.5% in 2021, according to the U.S. Census Bureau.
Which county has the lowest uninsured rate, all ages (US)?
Placer County, with 3.4% 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 B27010: people with no health insurance coverage as a percentage of the civilian noninstitutionalized population, calculated with stored inputs. Retrieved 2026-10-12.
Uninsured rate, all ages (US): other rankings
- Counties in Utah
- Counties in Louisiana
- Counties in Iowa
- Cities in Arkansas
- Cities in Oregon
- Cities in Virginia
Counties in California: more rankings
- Physical inactivity in adults, local model estimate
- Current asthma in adults, local model estimate
- Uninsured rate, ages 35 to 64 (US, ACS)
- Uninsured rate, ages 18 to 64 (US model-based estimate)
- Natural change, July to June
- Population speaking a language other than English at home
- Median household income
- Gini index