RANKING · 2024 ACS · 58 SHOWN OF 58

Oldest by median age, California counties

California counties ranked by median age of residents (2024 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

01Trinity County, CACA15,72054.9+23%

02Sierra County, CACA3,09854.7+25%

03Calaveras County, CACA46,60552.0+17%

04Plumas County, CACA18,58352.0+18%

05Mariposa County, CACA16,91851.2+19%

06Nevada County, CACA101,91150.1+16%

07Amador County, CACA41,87649.7+16%

08Tuolumne County, CACA53,16048.4+13%

09Modoc County, CACA8,42647.5+14%

10Marin County, CACA253,69447.4+15%

11Siskiyou County, CACA42,01347.2+10%

12El Dorado County, CACA192,32346.1+17%

13Inyo County, CACA18,15845.5+6%

14Lake County, CACA67,77244.1+3%

15Mendocino County, CACA88,12244.1+13%

16Napa County, CACA132,94942.9+12%

17Sonoma County, CACA486,44442.9+14%

18Placer County, CACA442,08142.5+12%

19Shasta County, CACA181,64841.7+7%

20Mono County, CACA12,50541.5+15%

21San Mateo County, CACA743,56840.9+11%

22Contra Costa County, CACA1,170,07040.5+11%

23San Luis Obispo County, CACA282,36740.4+8%

24San Francisco County, CACA826,07940.0+10%

25Tehama County, CACA64,66540.0+6%

26Del Norte County, CACA26,41039.9+10%

27Humboldt County, CACA131,64739.9+10%

28Alpine County, CACA1,04339.8+1%

29Santa Cruz County, CACA258,85239.8+14%

30Ventura County, CACA830,85139.6+16%

31Orange County, CACA3,149,50739.4+18%

32Solano County, CACA455,37639.2+16%

33Alameda County, CACA1,636,63039.0+13%

34Lassen County, CACA28,11738.3+11%

35Los Angeles County, CACA9,694,93438.2+19%

36Santa Clara County, CACA1,914,39138.1+12%

37Sacramento County, CACA1,618,46037.5+11%

38San Diego County, CACA3,282,24837.3+12%

39Riverside County, CACA2,544,91637.0+12%

40Sutter County, CACA98,78736.5+7%

41Butte County, CACA209,21136.2+1%

42Glenn County, CACA28,14136.2+7%

43San Benito County, CACA70,08236.1+15%

44Colusa County, CACA21,83635.9+14%

45Monterey County, CACA433,72935.5+12%

46San Joaquin County, CACA823,81535.4+11%

47Stanislaus County, CACA557,71934.9+10%

48San Bernardino County, CACA2,224,09134.7+15%

49Madera County, CACA167,92734.6+6%

50Santa Barbara County, CACA442,06534.6+4%

51Yuba County, CACA88,69134.2+9%

52Fresno County, CACA1,035,45633.5+12%

53Imperial County, CACA181,41133.2+7%

54Kern County, CACA927,06832.7+7%

55Kings County, CACA154,32732.5+8%

56Tulare County, CACA485,14632.1+10%

57Yolo County, CACA224,41032.1+9%

58Merced County, CACA297,26031.8+10%

SHOWING 1–58 OF 58

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES