Data / Rankings / Median age / Counties in California

Counties in California by median age

Trinity County had the highest median age of 58 counties in 2021, at 53.9 years. Tulare County had the lowest, at 31.3 years. The median was 38.6 years and the figure for California was 37 years. Source: the U.S. Census Bureau.

Highest53.9Trinity County
Lowest31.3Tulare County
Median38.658 counties
California37History

All counties, 2021

CSVChart (SVG)

Trinity CountyTrinity County: 53.9 years53.9Calaveras CountyCalaveras County: 52.3 years52.3Plumas CountyPlumas County: 51.8 years51.8Mariposa CountyMariposa County: 51.6 years51.6Nevada CountyNevada County: 50.1 years50.1Amador CountyAmador County: 49.7 years49.7Tuolumne CountyTuolumne County: 48.6 years48.6Alpine CountyAlpine County: 48.2 years48.2Modoc CountyModoc County: 47.8 years47.8Marin CountyMarin County: 47.1 years47.1Siskiyou CountySiskiyou County: 47.1 years47.1El Dorado CountyEl Dorado County: 46.2 years46.2Sierra CountySierra County: 45.9 years45.9Lake CountyLake County: 44.6 years44.6Inyo CountyInyo County: 44.5 years44.5Mendocino CountyMendocino County: 43.6 years43.6Sonoma CountySonoma County: 42.5 years42.5Napa CountyNapa County: 42.1 years42.1Placer CountyPlacer County: 42.1 years42.1Shasta CountyShasta County: 41.5 years41.5Mono CountyMono County: 40.3 years40.3Del Norte CountyDel Norte County: 40.1 years40.1San Mateo CountySan Mateo County: 40 years40Tehama CountyTehama County: 40 years40Contra Costa CountyContra Costa County: 39.9 years39.9San Luis Obispo CountySan Luis Obispo County: 39.7 years39.7Humboldt CountyHumboldt County: 39.1 years39.1San Francisco CountySan Francisco County: 38.7 years38.7Ventura CountyVentura County: 38.7 years38.7Orange CountyOrange County: 38.5 years38.5Santa Cruz CountySanta Cruz County: 38.5 years38.5Solano CountySolano County: 38.5 years38.5Alameda CountyAlameda County: 38 years38Santa Clara CountySanta Clara County: 37.5 years37.5Lassen CountyLassen County: 37.3 years37.3Los Angeles CountyLos Angeles County: 37 years37Butte CountyButte County: 36.6 years36.6Sacramento CountySacramento County: 36.6 years36.6San Diego CountySan Diego County: 36.3 years36.3Riverside CountyRiverside County: 36 years36Sutter CountySutter County: 35.8 years35.8San Benito CountySan Benito County: 35.7 years35.7Colusa CountyColusa County: 35.6 years35.6Glenn CountyGlenn County: 35.5 years35.5Monterey CountyMonterey County: 34.9 years34.9San Joaquin CountySan Joaquin County: 34.6 years34.6Stanislaus CountyStanislaus County: 34.4 years34.4Madera CountyMadera County: 34.3 years34.3Santa Barbara CountySanta Barbara County: 33.9 years33.9San Bernardino CountySan Bernardino County: 33.8 years33.8Yuba CountyYuba County: 33.2 years33.2Fresno CountyFresno County: 32.6 years32.6Imperial CountyImperial County: 32.5 years32.5Kern CountyKern County: 32.1 years32.1Kings CountyKings County: 32.1 years32.1Yolo CountyYolo County: 31.5 years31.5Merced CountyMerced County: 31.3 years31.3Tulare CountyTulare County: 31.3 years31.3
years. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2021
years
1Trinity County53.9
2Calaveras County52.3
3Plumas County51.8
4Mariposa County51.6
5Nevada County50.1
6Amador County49.7
7Tuolumne County48.6
8Alpine County48.2
9Modoc County47.8
10Marin County47.1
10Siskiyou County47.1
12El Dorado County46.2
13Sierra County45.9
14Lake County44.6
15Inyo County44.5
16Mendocino County43.6
17Sonoma County42.5
18Napa County42.1
18Placer County42.1
20Shasta County41.5
21Mono County40.3
22Del Norte County40.1
23San Mateo County40
23Tehama County40
25Contra Costa County39.9
26San Luis Obispo County39.7
27Humboldt County39.1
28San Francisco County38.7
28Ventura County38.7
30Orange County38.5
30Santa Cruz County38.5
30Solano County38.5
33Alameda County38
34Santa Clara County37.5
35Lassen County37.3
36Los Angeles County37
37Butte County36.6
37Sacramento County36.6
39San Diego County36.3
40Riverside County36
41Sutter County35.8
42San Benito County35.7
43Colusa County35.6
44Glenn County35.5
45Monterey County34.9
46San Joaquin County34.6
47Stanislaus County34.4
48Madera County34.3
49Santa Barbara County33.9
50San Bernardino County33.8
51Yuba County33.2
52Fresno County32.6
53Imperial County32.5
54Kern County32.1
54Kings County32.1
56Yolo County31.5
57Merced County31.3
57Tulare County31.3

Other periods

About this ranking

Age that divides the resident population into two halves of equal size. Spain and the EU: on 1 January. United States: American Community Survey five-year estimate, where the period shown is the last year of the five-year span.

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 B01002: median age, total population. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b01002.dat. Retrieved 2026-10-08.

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Questions

Which county has the highest median age?

Trinity County, with 53.9 years in 2021, according to the U.S. Census Bureau.

Which county has the lowest median age?

Tulare County, with 31.3 years 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 B01002: median age, total population. Retrieved 2026-10-08.

Median age: other rankings

Counties in California: more rankings