RANKING · 2020 CENSUS · 58 SHOWN OF 58

Oldest by median age, California counties · 2020

California counties ranked by median age of residents (2020 ACS). This list covers the 58 counties in California that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros ZIP codes

RELATEDLargest foreign-born population Most residents with a disability Largest veteran population Most uninsured people Largest senior population Most unmarried people

YEAR1990 2000 2010 2020 2024

RANKPLACESTATEPOPMEDIAN AGEVS 2000

01Sierra County, CACA3,09853.9+23%

02Plumas County, CACA18,58353.0+20%

03Mariposa County, CACA16,91852.1+21%

04Amador County, CACA41,87651.6+21%

05Calaveras County, CACA46,60551.6+16%

06Alpine County, CACA1,04350.1+27%

07Nevada County, CACA101,91149.7+15%

08Tuolumne County, CACA53,16048.9+14%

09Modoc County, CACA8,42648.7+17%

10Siskiyou County, CACA42,01348.5+13%

11Trinity County, CACA15,72047.6+7%

12Marin County, CACA253,69446.5+13%

13El Dorado County, CACA192,32346.3+18%

14Lake County, CACA67,77245.0+5%

15Inyo County, CACA18,15844.8+5%

16Mendocino County, CACA88,12243.2+11%

17Napa County, CACA132,94942.9+12%

18Shasta County, CACA181,64842.8+10%

19Sonoma County, CACA486,44442.6+14%

20Placer County, CACA442,08142.4+12%

21San Luis Obispo County, CACA282,36741.4+11%

22Tehama County, CACA64,66540.4+7%

23Del Norte County, CACA26,41040.2+10%

24Santa Cruz County, CACA258,85240.2+15%

25Contra Costa County, CACA1,170,07040.1+10%

26San Mateo County, CACA743,56839.9+8%

27Mono County, CACA12,50539.5+10%

28Ventura County, CACA830,85139.5+15%

29Humboldt County, CACA131,64739.1+8%

30Orange County, CACA3,149,50739.0+17%

31Solano County, CACA455,37639.0+15%

32San Francisco County, CACA826,07938.2+5%

33Butte County, CACA209,21137.9+6%

34Alameda County, CACA1,636,63037.7+9%

35Glenn County, CACA28,14137.5+11%

36Los Angeles County, CACA9,694,93437.5+17%

37Santa Clara County, CACA1,914,39137.5+10%

38Lassen County, CACA28,11737.2+8%

39San Diego County, CACA3,282,24837.1+12%

40Sacramento County, CACA1,618,46036.9+9%

41Sutter County, CACA98,78736.9+8%

42Riverside County, CACA2,544,91636.8+11%

43San Benito County, CACA70,08236.6+17%

44Santa Barbara County, CACA442,06535.7+7%

45Colusa County, CACA21,83635.5+13%

46Stanislaus County, CACA557,71935.5+12%

47San Joaquin County, CACA823,81535.4+11%

48Madera County, CACA167,92735.0+7%

49Monterey County, CACA433,72935.0+10%

50San Bernardino County, CACA2,224,09134.9+15%

51Imperial County, CACA181,41134.6+12%

52Yuba County, CACA88,69134.3+9%

53Fresno County, CACA1,035,45633.3+11%

54Yolo County, CACA224,41033.3+13%

55Kings County, CACA154,32732.9+9%

56Kern County, CACA927,06832.8+7%

57Tulare County, CACA485,14632.3+11%

58Merced County, CACA297,26032.0+10%

SHOWING 1–58 OF 58

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU DECENNIAL CENSUS