RANKING · 1990 CENSUS · 58 SHOWN OF 58

Oldest by median age, California counties · 1990

California counties ranked by median age of residents (1990 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 –

01Sierra County, CACA3,09843.7–

02Lake County, CACA67,77240.7–

03Calaveras County, CACA46,60539.8–

04Mariposa County, CACA16,91839.5–

05Nevada County, CACA101,91139.4–

06Plumas County, CACA18,58339.0–

07Inyo County, CACA18,15838.9–

08Marin County, CACA253,69438.2–

09Trinity County, CACA15,72037.9–

10Amador County, CACA41,87637.9–

11Tuolumne County, CACA53,16037.3–

12Modoc County, CACA8,42637.2–

13Siskiyou County, CACA42,01337.2–

14Napa County, CACA132,94936.5–

15Tehama County, CACA64,66536.0–

16San Francisco County, CACA826,07936.0–

17El Dorado County, CACA192,32335.6–

18Mendocino County, CACA88,12235.5–

19Placer County, CACA442,08135.2–

20San Mateo County, CACA743,56835.0–

21Shasta County, CACA181,64834.9–

22Sonoma County, CACA486,44434.9–

23Contra Costa County, CACA1,170,07034.2–

24Butte County, CACA209,21134.0–

25Alpine County, CACA1,04333.6–

26Santa Cruz County, CACA258,85233.3–

27San Luis Obispo County, CACA282,36733.3–

28Humboldt County, CACA131,64733.2–

29Alameda County, CACA1,636,63032.9–

30Glenn County, CACA28,14132.5–

31Sutter County, CACA98,78732.5–

32Mono County, CACA12,50532.3–

33Del Norte County, CACA26,41032.3–

34Colusa County, CACA21,83632.2–

35Madera County, CACA167,92732.1–

36Santa Clara County, CACA1,914,39132.0–

37Sacramento County, CACA1,618,46032.0–

38Lassen County, CACA28,11731.9–

39Ventura County, CACA830,85131.8–

40Santa Barbara County, CACA442,06531.8–

41Riverside County, CACA2,544,91631.7–

42Orange County, CACA3,149,50731.5–

43San Diego County, CACA3,282,24831.0–

44San Joaquin County, CACA823,81531.0–

45Solano County, CACA455,37631.0–

46Los Angeles County, CACA9,694,93430.8–

47San Benito County, CACA70,08230.7–

48Stanislaus County, CACA557,71930.7–

49Monterey County, CACA433,72929.8–

50Kern County, CACA927,06829.8–

51Yuba County, CACA88,69129.7–

52Tulare County, CACA485,14629.5–

53Fresno County, CACA1,035,45629.5–

54San Bernardino County, CACA2,224,09129.4–

55Yolo County, CACA224,41028.9–

56Imperial County, CACA181,41128.8–

57Kings County, CACA154,32728.4–

58Merced County, CACA297,26028.1–

SHOWING 1–58 OF 58

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