Ranking of California Counties By Number of People and Percentage of Population With No Health Insurance Coverage in 2021 (ACS-5Yrs)

Updated on October 27, 2025.

Based on the US Census ACS-5Yrs estimates, in 2021, the percentage of the California population without a health insurance coverage was 7.19% (i.e. 2,800,277 people). Percentagewise, among all California counties, Sierra County had the highest percentage of its population with no health insurance coverage (15.53%), followed by Mono County (12.54%), and Modoc County (12.00%).

In numerical terms, Los Angeles County had the highest number of people without a health insurance coverage (904,431), followed by San Diego County (237,716), and Orange County (224,932).

The charts below shows the top 10 counties by the number of people and percentage of the population without a health insurance coverage. The tables below shows the ranking for all California counties.

You can see similar information for other types of health insurance coverages.

You can also see similar information for other states.

Ranking of California Counties By Percentage of Population With No Health Insurance Coverage in 2021
Sierra County
Mono County
Modoc County
Trinity County
Santa Barbara County
Glenn County
Monterey County
Mendocino County
Los Angeles County
Merced County
Ranking of California Counties By Number of People With No Health Insurance Coverage in 2021
Los Angeles County
San Diego County
Orange County
Riverside County
San Bernardino County
Sacramento County
Santa Clara County
Fresno County
Alameda County
Kern County
Ranking of California Counties By Percentage of Population With No Health Insurance Coverage in 2021
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Rank County Percentage of Population (%)
1 Sierra County 15.53
2 Mono County 12.54
3 Modoc County 12.00
4 Trinity County 10.46
5 Santa Barbara County 10.14
6 Glenn County 10.04
7 Monterey County 9.95
8 Mendocino County 9.71
9 Los Angeles County 9.09
10 Merced County 8.76
11 San Bernardino County 8.47
12 Colusa County 8.44
13 Ventura County 8.36
14 Riverside County 8.26
15 Madera County 8.20
16 Kern County 8.02
17 Humboldt County 7.68
18 Tulare County 7.67
19 Kings County 7.64
20 San Diego County 7.46
21 Fresno County 7.29
22 Orange County 7.10
23 Inyo County 7.08
24 Yuba County 7.07
25 Shasta County 6.82
26 Lake County 6.69
27 Alpine County 6.62
28 Calaveras County 6.60
28 Imperial County 6.60
28 Sutter County 6.60
29 Siskiyou County 6.52
30 Tehama County 6.50
30 Tuolumne County 6.50
31 Mariposa County 6.49
32 San Benito County 6.42
33 Butte County 6.39
34 San Joaquin County 6.38
35 Stanislaus County 6.05
36 Napa County 5.96
37 San Luis Obispo County 5.93
38 Sonoma County 5.90
39 Lassen County 5.77
40 Nevada County 5.48
41 Sacramento County 5.45
41 Santa Cruz County 5.45
42 Del Norte County 5.20
43 Solano County 4.76
44 Contra Costa County 4.73
45 Amador County 4.72
46 Yolo County 4.47
47 Plumas County 4.42
48 Alameda County 4.29
49 Santa Clara County 4.15
50 El Dorado County 4.10
51 San Mateo County 3.78
52 San Francisco County 3.61
53 Marin County 3.49
54 Placer County 3.42
Ranking of California Counties By Number of People With NO Health Insurance Coverage in 2021
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Rank County Number of People
1 Los Angeles County 904431
2 San Diego County 237716
3 Orange County 224932
4 Riverside County 197139
5 San Bernardino County 179898
6 Sacramento County 84824
7 Santa Clara County 79687
8 Fresno County 72292
9 Alameda County 71358
10 Kern County 70413
11 Ventura County 70005
12 Contra Costa County 54756
13 San Joaquin County 48480
14 Santa Barbara County 44617
15 Monterey County 42096
16 Tulare County 35797
17 Stanislaus County 33169
18 San Francisco County 31130
19 Sonoma County 28827
20 San Mateo County 28663
21 Merced County 24212
22 Solano County 20892
23 San Luis Obispo County 16399
24 Santa Cruz County 14751
25 Butte County 13781
26 Placer County 13594
27 Shasta County 12299
28 Madera County 12145
29 Imperial County 11227
30 Humboldt County 10454
31 Kings County 10268
32 Yolo County 9611
33 Marin County 9030
34 Mendocino County 8803
35 Napa County 8180
36 El Dorado County 7768
37 Sutter County 6442
38 Nevada County 5534
39 Yuba County 5496
40 Lake County 4486
41 Tehama County 4212
42 San Benito County 4056
43 Tuolumne County 3392
44 Calaveras County 2967
45 Siskiyou County 2869
46 Glenn County 2851
47 Colusa County 1826
48 Amador County 1728
49 Mono County 1640
50 Trinity County 1636
51 Lassen County 1340
52 Inyo County 1306
53 Del Norte County 1299
54 Mariposa County 1107
55 Modoc County 1022
56 Plumas County 861
57 Sierra County 474
58 Alpine County 89