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. The median across all 58 is 39.1.

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SAME RANKING BYCities States Metros ZIP codes

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 2026-09-11 · DATA: US CENSUS BUREAU DECENNIAL CENSUS