Data / Rankings / Uninsured rate, ages 18 to 64 (US model-based estimate) / Counties in California

Counties in California by uninsured rate, ages 18 to 64 (US model-based estimate)

Monterey County had the highest uninsured rate, ages 18 to 64 (US model-based estimate) of 58 counties in 2021, at 15.5%. Placer County had the lowest, at 4.6%. The median was 9% and the figure for California was 9.8%. Source: the U.S. Census Bureau.

Highest15.5Monterey County
Lowest4.6Placer County
Median958 counties
California9.8History

All counties, 2021

Monterey County: 15.5 %Monterey County15.5Glenn County: 14.7 %Glenn County14.7Colusa County: 14.1 %Colusa County14.1Madera County: 14 %Madera County14Tulare County: 14 %Tulare County14Merced County: 12.5 %Merced County12.5Los Angeles County: 12.3 %Los Angeles County12.3Santa Barbara County: 12.3 %Santa Barbara County12.3Mono County: 11.9 %Mono County11.9San Bernardino County: 11.9 %San Bernardino County11.9Ventura County: 11.7 %Ventura County11.7Kern County: 11.6 %Kern County11.6Riverside County: 11.6 %Riverside County11.6Mendocino County: 11.4 %Mendocino County11.4Stanislaus County: 10.9 %Stanislaus County10.9Sutter County: 10.8 %Sutter County10.8Imperial County: 10.6 %Imperial County10.6Modoc County: 10.5 %Modoc County10.5Del Norte County: 10.4 %Del Norte County10.4Lake County: 10.2 %Lake County10.2Fresno County: 9.9 %Fresno County9.9Kings County: 9.7 %Kings County9.7San Joaquin County: 9.7 %San Joaquin County9.7Orange County: 9.4 %Orange County9.4Tehama County: 9.4 %Tehama County9.4Inyo County: 9.3 %Inyo County9.3San Benito County: 9.2 %San Benito County9.2Yuba County: 9.1 %Yuba County9.1Butte County: 9 %Butte County9Santa Cruz County: 9 %Santa Cruz County9Shasta County: 9 %Shasta County9Siskiyou County: 9 %Siskiyou County9Sonoma County: 9 %Sonoma County9Napa County: 8.9 %Napa County8.9San Diego County: 8.9 %San Diego County8.9Humboldt County: 8.8 %Humboldt County8.8Mariposa County: 8.5 %Mariposa County8.5Alpine County: 8.3 %Alpine County8.3Calaveras County: 7.8 %Calaveras County7.8Trinity County: 7.8 %Trinity County7.8San Luis Obispo County: 7.7 %San Luis Obispo County7.7Yolo County: 7.7 %Yolo County7.7Sierra County: 7.5 %Sierra County7.5Lassen County: 7.3 %Lassen County7.3Nevada County: 7.3 %Nevada County7.3Sacramento County: 7.3 %Sacramento County7.3Tuolumne County: 7.1 %Tuolumne County7.1Plumas County: 6.9 %Plumas County6.9Solano County: 6.8 %Solano County6.8Amador County: 6.5 %Amador County6.5Contra Costa County: 6.1 %Contra Costa County6.1Alameda County: 5.8 %Alameda County5.8El Dorado County: 5.6 %El Dorado County5.6Marin County: 5.5 %Marin County5.5San Mateo County: 5.5 %San Mateo County5.5Santa Clara County: 5.3 %Santa Clara County5.3San Francisco County: 4.9 %San Francisco County4.9Placer County: 4.6 %Placer County4.6
%. Source: 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.

Full ranking

RankCounties2021 (%)Change on 2020
1Monterey County15.5+1.4 pts
2Glenn County14.7-0.5 pts
3Colusa County14.1-1.7 pts
4Madera County14+0.9 pts
4Tulare County14+1.6 pts
6Merced County12.5-1.1 pts
7Los Angeles County12.3-0.2 pts
7Santa Barbara County12.3-2 pts
9Mono County11.9-0.2 pts
9San Bernardino County11.9+0.9 pts
11Ventura County11.7+1.7 pts
12Kern County11.6-0.8 pts
12Riverside County11.6-0.2 pts
14Mendocino County11.4-2.1 pts
15Stanislaus County10.9+1.6 pts
16Sutter County10.8-0.4 pts
17Imperial County10.6-1.3 pts
18Modoc County10.5+0.2 pts
19Del Norte County10.4+1.7 pts
20Lake County10.2+0.9 pts
21Fresno County9.9-1.7 pts
22Kings County9.7-1.8 pts
22San Joaquin County9.7-0.2 pts
24Orange County9.4+0.3 pts
24Tehama County9.4-0.4 pts
26Inyo County9.3-2.2 pts
27San Benito County9.2-0.6 pts
28Yuba County9.1-0.8 pts
29Butte County9+0.3 pts
29Santa Cruz County9-0.2 pts
29Shasta County9+0.7 pts
29Siskiyou County9-0.3 pts
29Sonoma County9+0.7 pts
34Napa County8.9-1.1 pts
34San Diego County8.9-0.8 pts
36Humboldt County8.8-0.4 pts
37Mariposa County8.5-0.6 pts
38Alpine County8.3-3.8 pts
39Calaveras County7.8-0.5 pts
39Trinity County7.8-1 pts
41San Luis Obispo County7.7-0.3 pts
41Yolo County7.7+0.8 pts
43Sierra County7.5-0.9 pts
44Lassen County7.3+1.9 pts
44Nevada County7.3+0.2 pts
44Sacramento County7.3-0.6 pts
47Tuolumne County7.1-0.5 pts
48Plumas County6.9-0.3 pts
49Solano County6.8-0.5 pts
50Amador County6.5-1 pts
51Contra Costa County6.1-0.4 pts
52Alameda County5.80 pts
53El Dorado County5.6-0.6 pts
54Marin County5.5+0.6 pts
54San Mateo County5.5+0.4 pts
56Santa Clara County5.3-0.7 pts
57San Francisco County4.9-0.5 pts
58Placer County4.6-0.7 pts

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-2021-csv.zip. 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). 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), 2021) [Data set]. Retrieved October 12, 2026, from https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-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), 2021. U.S. Census Bureau, 6 Aug. 2026, https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip. Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2021. 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), 2021. Dataset. Accessed October 12, 2026. https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip. Also distributed by Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2021.

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), 2021 [Dataset]. Available at: https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip, via Invokely: https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2021 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_california_by_2021,
  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), 2021}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www2.census.gov/programs-surveys/sahie/datasets/time-series/estimates-acs/sahie-2021-csv.zip},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2021. 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-2021-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), 2021
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-2021-csv.zip
L2  - https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/uninsured-rate-ages-18-64/california-counties?period=2021.
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-2021-csv.zip. Retrieved 2026-10-12.
ER  -
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Questions

Which county has the highest uninsured rate, ages 18 to 64 (US model-based estimate)?

Monterey County, with 15.5% in 2021, according to the U.S. Census Bureau.

Which county has the lowest uninsured rate, ages 18 to 64 (US model-based estimate)?

Placer County, with 4.6% 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, 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