RANKING · 2010 CENSUS · 58 SHOWN OF 58

Oldest by median age, California counties · 2010

California counties ranked by median age of residents (2010 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, CACA3,09850.9+16%

02Plumas County, CACA18,58349.6+12%

03Trinity County, CACA15,72049.3+11%

04Calaveras County, CACA46,60549.2+10%

05Mariposa County, CACA16,91849.2+15%

06Amador County, CACA41,87648.2+13%

07Nevada County, CACA101,91147.6+10%

08Tuolumne County, CACA53,16047.3+10%

09Siskiyou County, CACA42,01347.0+9%

10Alpine County, CACA1,04346.7+19%

11Modoc County, CACA8,42646.1+10%

12Inyo County, CACA18,15845.6+7%

13Lake County, CACA67,77245.0+5%

14Marin County, CACA253,69444.5+8%

15El Dorado County, CACA192,32343.6+11%

16Shasta County, CACA181,64841.8+7%

17Mendocino County, CACA88,12241.5+7%

18Placer County, CACA442,08140.3+6%

19Sonoma County, CACA486,44439.9+6%

20Napa County, CACA132,94939.7+4%

21Tehama County, CACA64,66539.5+4%

22San Luis Obispo County, CACA282,36739.4+6%

23San Mateo County, CACA743,56839.3+7%

24Del Norte County, CACA26,41039.1+7%

25Contra Costa County, CACA1,170,07038.5+6%

26San Francisco County, CACA826,07938.5+5%

27Butte County, CACA209,21137.2+4%

28Mono County, CACA12,50537.2+3%

29Humboldt County, CACA131,64737.1+2%

30Lassen County, CACA28,11737.1+7%

31Santa Cruz County, CACA258,85236.9+5%

32Solano County, CACA455,37636.9+9%

33Alameda County, CACA1,636,63036.6+6%

34Orange County, CACA3,149,50736.2+9%

35Santa Clara County, CACA1,914,39136.2+6%

36Ventura County, CACA830,85136.2+6%

37Glenn County, CACA28,14135.3+5%

38Los Angeles County, CACA9,694,93434.8+9%

39Sacramento County, CACA1,618,46034.8+3%

40San Diego County, CACA3,282,24834.6+4%

41Sutter County, CACA98,78734.5+1%

42San Benito County, CACA70,08234.3+9%

43Riverside County, CACA2,544,91633.7+2%

44Santa Barbara County, CACA442,06533.6+1%

45Colusa County, CACA21,83633.5+6%

46Madera County, CACA167,92733.0+1%

47Monterey County, CACA433,72932.9+4%

48Stanislaus County, CACA557,71932.9+4%

49San Joaquin County, CACA823,81532.7+3%

50Yuba County, CACA88,69132.1+2%

51Imperial County, CACA181,41131.9+3%

52San Bernardino County, CACA2,224,09131.7+5%

53Kings County, CACA154,32731.1+3%

54Kern County, CACA927,06830.7+0%

55Fresno County, CACA1,035,45630.6+2%

56Yolo County, CACA224,41030.4+3%

57Merced County, CACA297,26029.6+2%

58Tulare County, CACA485,14629.6+1%

SHOWING 1–58 OF 58

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