Ranking of California Counties By Percentage of Population Aged 25 years and above with an Educational attainment of High School Graduate or Equivalent in 2021 (ACS-5Yrs)

Updated on September 3, 2025.

Based on the US Census ACS-5Yrs estimates, in 2021, the percentage of the population of California (aged 25 years and above) who had an educational attainment of High School Graduate or Equivalent was 20.44%. Among all California counties, Trinity County had the highest percentage of its population (aged 25 years and above) with an educational attainment of High School Graduate or Equivalent (38.42%), followed by Modoc County (32.54%), and Lassen County (32.44%).

The chart below shows the top 10 California counties, and the table below shows the ranking of all California counties.

You can see similar information for other educational attainments.

You can also see similar information for other states and for the United States.

Ranking of California Counties By Percentage of Population (Aged 25yrs+) with an Educational Attainment of High School Graduate or Equivalent in 2021
Trinity County
Modoc County
Lassen County
Del Norte County
Calaveras County
Amador County
Inyo County
Colusa County
Glenn County
Stanislaus County
Ranking of California Counties By Percentage of Population (Aged 25yrs+) with an Educational Attainment of High School Graduate or Equivalent in 2021
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Rank County Percentage of Population (Aged 25yrs+) (%)
1 Trinity County 38.42
2 Modoc County 32.54
3 Lassen County 32.44
4 Del Norte County 30.97
5 Calaveras County 30.94
6 Amador County 30.65
7 Inyo County 30.47
8 Colusa County 30.46
9 Glenn County 30.27
10 Stanislaus County 29.97
11 Lake County 29.89
12 Sierra County 29.52
13 Tehama County 28.99
14 San Joaquin County 28.76
15 Kern County 27.57
16 Plumas County 27.30
17 Siskiyou County 27.07
18 Riverside County 26.93
19 San Bernardino County 26.87
20 San Benito County 26.79
21 Merced County 26.52
22 Tulare County 26.48
23 Mendocino County 26.32
24 Kings County 26.12
25 Shasta County 25.83
26 Alpine County 25.70
27 Imperial County 25.56
28 Tuolumne County 25.21
29 Sutter County 24.52
30 Solano County 23.77
31 Madera County 23.26
32 Yuba County 23.20
33 Humboldt County 23.08
34 Fresno County 22.69
35 Mariposa County 22.41
36 Mono County 22.37
37 Butte County 22.30
38 Sacramento County 22.01
39 El Dorado County 20.79
40 Los Angeles County 20.39
41 Monterey County 20.29
42 Ventura County 19.77
43 San Luis Obispo County 19.55
44 Nevada County 19.04
45 Sonoma County 18.31
46 San Diego County 18.20
47 Napa County 17.96
48 Yolo County 17.74
49 Placer County 17.58
50 Contra Costa County 17.47
51 Santa Barbara County 17.26
52 Orange County 17.24
53 Alameda County 16.65
54 Santa Cruz County 15.91
55 San Mateo County 14.89
56 Santa Clara County 13.70
57 San Francisco County 11.37
58 Marin County 10.17