RANKING · 2010 CENSUS · 58 SHOWN OF 58

Most densely populated, California counties · 2010

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, CACA826,07917,243+4%

02Orange County, CACA3,149,5073,797+6%

03Los Angeles County, CACA9,694,9342,418+3%

04Alameda County, CACA1,636,6302,048+5%

05San Mateo County, CACA743,5681,602+2%

06Sacramento County, CACA1,618,4601,470+16%

07Contra Costa County, CACA1,170,0701,463+11%

08Santa Clara County, CACA1,914,3911,380+6%

09San Diego County, CACA3,282,248735+10%

10Santa Cruz County, CACA258,852589+3%

11Solano County, CACA455,376503+5%

12San Joaquin County, CACA823,815492+22%

13Marin County, CACA253,694485+2%

14Ventura County, CACA830,851447+9%

15Stanislaus County, CACA557,719344+15%

16Sonoma County, CACA486,444307+6%

17Riverside County, CACA2,544,916304+42%

18Placer County, CACA442,081248+40%

19Yolo County, CACA224,410198+19%

20Napa County, CACA132,949182+10%

21Sutter County, CACA98,787157+20%

22Fresno County, CACA1,035,456156+16%

23Santa Barbara County, CACA442,065155+6%

24Butte County, CACA209,211134+8%

25Merced County, CACA297,260132+21%

26Monterey County, CACA433,729126+3%

27Yuba County, CACA88,691114+20%

28Kings County, CACA154,327110+18%

29El Dorado County, CACA192,323106+16%

30Kern County, CACA927,068103+27%

31Nevada County, CACA101,911103+7%

32San Bernardino County, CACA2,224,091101+19%

33Tulare County, CACA485,14692+20%

34San Luis Obispo County, CACA282,36782+9%

35Madera County, CACA167,92771+23%

36Amador County, CACA41,87664+9%

37Lake County, CACA67,77252+11%

38Shasta County, CACA181,64847+9%

39Calaveras County, CACA46,60545+12%

40Imperial County, CACA181,41142+23%

41San Benito County, CACA70,08240+4%

42Humboldt County, CACA131,64738+6%

43Del Norte County, CACA26,41028+4%

44Mendocino County, CACA88,12225+2%

45Tuolumne County, CACA53,16025+2%

46Tehama County, CACA64,66522+13%

47Glenn County, CACA28,14121+6%

48Colusa County, CACA21,83619+14%

49Mariposa County, CACA16,91813+7%

50Plumas County, CACA18,5838−4%

51Lassen County, CACA28,1178+3%

52Siskiyou County, CACA42,0137+1%

53Mono County, CACA12,5055+10%

54Trinity County, CACA15,7204+6%

55Sierra County, CACA3,0983−9%

56Modoc County, CACA8,4262+3%

57Inyo County, CACA18,1582+3%

58Alpine County, CACA1,0432−3%

SHOWING 1–58 OF 58

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