RANKING · 2020 CENSUS · 58 SHOWN OF 58

Most densely populated, California counties · 2020

California counties ranked by residents per square mile (2023). This list covers the 58 counties in California that qualify, ranked against each other statewide.

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YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS 2000

01San Francisco County, CACA826,07918,714+13%

02Orange County, CACA3,149,5074,020+12%

03Los Angeles County, CACA9,694,9342,466+5%

04Alameda County, CACA1,636,6302,281+17%

05San Mateo County, CACA743,5681,704+8%

06Sacramento County, CACA1,618,4601,642+30%

07Contra Costa County, CACA1,170,0701,626+23%

08Santa Clara County, CACA1,914,3911,500+15%

09San Diego County, CACA3,282,248783+17%

10Santa Cruz County, CACA258,852609+6%

11San Joaquin County, CACA823,815560+38%

12Solano County, CACA455,376552+15%

13Marin County, CACA253,694504+6%

14Ventura County, CACA830,851458+12%

15Stanislaus County, CACA557,719370+24%

16Riverside County, CACA2,544,916335+56%

17Sonoma County, CACA486,444310+7%

18Placer County, CACA442,081288+63%

19Yolo County, CACA224,410214+28%

20Napa County, CACA132,949184+11%

21Fresno County, CACA1,035,456169+26%

22Sutter County, CACA98,787165+26%

23Santa Barbara County, CACA442,065164+12%

24Merced County, CACA297,260145+34%

25Monterey County, CACA433,729134+9%

26Butte County, CACA209,211129+4%

27Yuba County, CACA88,691129+35%

28El Dorado County, CACA192,323112+22%

29Kern County, CACA927,068112+37%

30Kings County, CACA154,327110+18%

31San Bernardino County, CACA2,224,091109+28%

32Nevada County, CACA101,911107+11%

33Tulare County, CACA485,14698+29%

34San Luis Obispo County, CACA282,36786+14%

35Madera County, CACA167,92773+27%

36Amador County, CACA41,87668+15%

37Lake County, CACA67,77254+17%

38Shasta County, CACA181,64848+12%

39San Benito County, CACA70,08246+21%

40Calaveras County, CACA46,60544+12%

41Imperial County, CACA181,41143+26%

42Humboldt County, CACA131,64738+8%

43Del Norte County, CACA26,41028+1%

44Mendocino County, CACA88,12226+6%

45Tuolumne County, CACA53,16025+2%

46Tehama County, CACA64,66522+17%

47Glenn County, CACA28,14122+9%

48Colusa County, CACA21,83619+16%

49Mariposa County, CACA16,91812+0%

50Plumas County, CACA18,5838−5%

51Lassen County, CACA28,1177−3%

52Siskiyou County, CACA42,0137−1%

53Trinity County, CACA15,7205+24%

54Mono County, CACA12,5054+3%

55Sierra County, CACA3,0983−9%

56Modoc County, CACA8,4262−8%

57Inyo County, CACA18,1582+6%

58Alpine County, CACA1,0432−0%

SHOWING 1–58 OF 58

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UPDATED 2026-06-02 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES