Counties in California by uninsured rate, ages 18 to 64 (US model-based estimate)
Colusa County had the highest uninsured rate, ages 18 to 64 (US model-based estimate) of 58 counties in 2020, at 15.8%. Marin County had the lowest, at 4.9%. The median was 9.3% and the figure for California was 10%. Source: the U.S. Census Bureau.
All counties, 2020
Full ranking
Other periods
About this ranking
People aged 18 to 64 without health insurance coverage of any kind, as a percentage of all people aged 18 to 64. United States: Census Bureau Small Area Health Insurance Estimates (SAHIE) for states and counties, all races, both sexes and all income levels.
A model-based single-year estimate that combines the American Community Survey with administrative records and population estimates, so every county gets a figure. Covers states and counties only, because the SAHIE dataset files have no national row. The Census Bureau advises comparing years from 2008 on only; 2013 is the updated release. Working-age adults; the rate for everyone under 65 is uninsured_rate_under_65.
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. Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2020-csv.zip. Retrieved 2026-10-12.Citation styles
APA 7
U.S. Census Bureau. (2026). Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties (Counties in California by uninsured rate, ages 18 to 64 (US model-based estimate), 2020) [Data set]. Retrieved October 12, 2026, from https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2020-csv.zip
MLA 9
Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties, Counties in California by uninsured rate, ages 18 to 64 (US model-based estimate), 2020. U.S. Census Bureau, 6 Aug. 2026, https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2020-csv.zip. Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2020. Accessed 12 Oct. 2026.
Chicago (author-date)
U.S. Census Bureau. 2026. Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. Counties in California by uninsured rate, ages 18 to 64 (US model-based estimate), 2020. Dataset. Accessed October 12, 2026. https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2020-csv.zip. Also distributed by Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2020.
Harvard
U.S. Census Bureau (2026) Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties, Counties in California by uninsured rate, ages 18 to 64 (US model-based estimate), 2020 [Dataset]. Available at: https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2020-csv.zip, via Invokely: https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2020 (Accessed: 12 October 2026).
BibTeX
@misc{census_counties_in_california_by_2020,
author = {{U.S. Census Bureau}},
title = {{Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties: Counties in California by uninsured rate, ages 18 to 64 (US model-based estimate), 2020}},
year = {2026},
howpublished = {Data set},
url = {https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2020-csv.zip},
urldate = {2026-10-12},
note = {Accessed via Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2020. Publisher attribution: U.S. Census Bureau. Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2020-csv.zip. Retrieved 2026-10-12.},
}
RIS
TY - DATA
AU - U.S. Census Bureau
TI - Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties: Counties in California by uninsured rate, ages 18 to 64 (US model-based estimate), 2020
PY - 2026
DA - 2026/08/06
PB - U.S. Census Bureau
DB - Invokely
UR - https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2020-csv.zip
L2 - https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2020
Y2 - 2026/10/12
N1 - Accessed via Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2020.
N1 - Publisher attribution: U.S. Census Bureau. Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2020-csv.zip. 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, ages 18 to 64 (US model-based estimate) using official data, and cite the source.
rank_places {"indicator":"uninsured_rate_18_64","level":"province","within":"California","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=uninsured_rate_18_64&level=province&within=California&limit=10Questions
Which county has the highest uninsured rate, ages 18 to 64 (US model-based estimate)?
Colusa County, with 15.8% in 2020, according to the U.S. Census Bureau.
Which county has the lowest uninsured rate, ages 18 to 64 (US model-based estimate)?
Marin County, with 4.9% in 2020.
Where does this ranking come from?
Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Small Area Health Insurance Estimates (SAHIE): percent uninsured, ages 18 to 64, all races, both sexes, all income levels, states and counties. Retrieved 2026-10-12.
Uninsured rate, ages 18 to 64 (US model-based estimate): other rankings
Counties in California: more rankings
- Current asthma in adults, local model estimate
- Adult obesity rate, local model estimate
- Uninsured rate, ages 19 to 34 (US, ACS)
- High blood pressure in adults, local model estimate
- Median household income (US single-year estimate)
- Female population share
- Deaths, July to June
- White (non-Hispanic) population share