RANKING · 2025 ESTIMATES · 58 SHOWN OF 58

Most densely populated, California counties

California counties ranked by residents per square mile (2025). This list covers the 58 counties in California that qualify, ranked against each other statewide. The median across all 58 is 113.

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SAME RANKING BYCities States Metros

YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS 2000

01San Francisco County, CACA826,07917,689+6%

02Orange County, CACA3,149,5073,972+11%

03Los Angeles County, CACA9,694,9342,388+2%

04Alameda County, CACA1,636,6302,219+13%

05▲1Sacramento County, CACA1,618,4601,677+32%

06▼1San Mateo County, CACA743,5681,658+5%

07Contra Costa County, CACA1,170,0701,632+23%

08Santa Clara County, CACA1,914,3911,483+14%

09San Diego County, CACA3,282,248780+17%

10▲1San Joaquin County, CACA823,815592+46%

11▼1Santa Cruz County, CACA258,852582+1%

12Solano County, CACA455,376554+15%

13Marin County, CACA253,694488+3%

14Ventura County, CACA830,851451+10%

15Stanislaus County, CACA557,719373+25%

16Riverside County, CACA2,544,916353+65%

17▲1Placer County, CACA442,081314+78%

18▼1Sonoma County, CACA486,444309+6%

19Yolo County, CACA224,410222+33%

20Napa County, CACA132,949177+7%

21Fresno County, CACA1,035,456174+30%

22Sutter County, CACA98,787164+25%

23Santa Barbara County, CACA442,065162+11%

24Merced County, CACA297,260153+41%

25▲2Yuba County, CACA88,691140+47%

26▼1Monterey County, CACA433,729132+8%

27▼1Butte County, CACA209,211128+3%

28▲1Kern County, CACA927,068114+40%

29▼1El Dorado County, CACA192,323113+23%

30Kings County, CACA154,327111+19%

31San Bernardino County, CACA2,224,091111+30%

32Nevada County, CACA101,911106+11%

33Tulare County, CACA485,146101+32%

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

35Madera County, CACA167,92779+36%

36Amador County, CACA41,87670+19%

37Lake County, CACA67,77254+16%

38▲1San Benito County, CACA70,08250+32%

39▼1Shasta County, CACA181,64848+11%

40Calaveras County, CACA46,60546+15%

41Imperial County, CACA181,41143+27%

42Humboldt County, CACA131,64737+4%

43Del Norte County, CACA26,41026−4%

44Mendocino County, CACA88,12225+2%

45Tuolumne County, CACA53,16024−2%

46Tehama County, CACA64,66522+15%

47Glenn County, CACA28,14121+6%

48Colusa County, CACA21,83619+16%

49Mariposa County, CACA16,91812−1%

50Plumas County, CACA18,5837−11%

51▲1Siskiyou County, CACA42,0137−5%

52▼1Lassen County, CACA28,1176−17%

53Trinity County, CACA15,7205+21%

54Mono County, CACA12,5054−3%

55Sierra County, CACA3,0983−13%

56Modoc County, CACA8,4262−11%

57Inyo County, CACA18,1582+1%

58Alpine County, CACA1,0431−14%

SHOWING 1–58 OF 58

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UPDATED 2026-09-11 · DATA: US CENSUS BUREAU POPULATION ESTIMATES