RANKING · 2025 ESTIMATES · 102 SHOWN OF 102

Largest by population, Illinois counties

The most populous Illinois counties as of the 2025 population estimates. This list covers the 102 counties in Illinois that qualify, ranked against each other statewide.

IllinoisAll states All rankings

SAME RANKING BYCities States Metros ZIP codes

RELATEDFastest growing Fastest shrinking Most population gained Most population lost Most densely populated Most sparsely populated

YEAR1990 2000 2010 2020 2025

RANKPLACESTATETOTAL POPULATIONVS 2000

01Cook County, ILIL5,194,625−3%

02DuPage County, ILIL934,298+3%

03Lake County, ILIL719,339+12%

04Will County, ILIL712,253+42%

05Kane County, ILIL525,757+30%

06McHenry County, ILIL317,751+22%

07Winnebago County, ILIL283,674+2%

08Madison County, ILIL263,110+2%

09St. Clair County, ILIL250,708−2%

10Champaign County, ILIL209,972+17%

11Sangamon County, ILIL194,170+3%

12Peoria County, ILIL178,553−3%

13McLean County, ILIL171,419+14%

14Kendall County, ILIL145,470+167%

15Rock Island County, ILIL141,869−5%

16Tazewell County, ILIL130,049+1%

17LaSalle County, ILIL107,773−3%

18Kankakee County, ILIL105,525+2%

19DeKalb County, ILIL101,835+14%

20Macon County, ILIL99,300−13%

21Vermilion County, ILIL71,259−15%

22Williamson County, ILIL67,225+10%

23Adams County, ILIL64,267−6%

24Whiteside County, ILIL54,121−11%

25Grundy County, ILIL54,052+44%

26Boone County, ILIL53,568+28%

27Jackson County, ILIL52,501−12%

28Ogle County, ILIL51,399+1%

29Henry County, ILIL48,095−6%

30Knox County, ILIL47,767−14%

31Coles County, ILIL46,607−12%

32Macoupin County, ILIL43,748−11%

33Stephenson County, ILIL43,220−12%

34Woodford County, ILIL38,111+7%

35Clinton County, ILIL37,128+4%

36Franklin County, ILIL36,916−5%

37Marion County, ILIL36,382−13%

38Jefferson County, ILIL36,147−10%

39Livingston County, ILIL35,057−12%

40Monroe County, ILIL34,840+26%

41Effingham County, ILIL34,519+1%

42Christian County, ILIL33,443−5%

43Lee County, ILIL32,914−9%

44Fulton County, ILIL32,901−14%

45Morgan County, ILIL32,515−11%

46Bureau County, ILIL32,510−8%

47Randolph County, ILIL29,921−12%

48Montgomery County, ILIL28,076−8%

49Logan County, ILIL27,182−13%

50Iroquois County, ILIL26,150−17%

51McDonough County, ILIL25,916−21%

52Saline County, ILIL22,772−15%

53Jo Daviess County, ILIL21,594−3%

54Jersey County, ILIL21,160−2%

55Fayette County, ILIL20,790−5%

56Shelby County, ILIL20,576−10%

57Perry County, ILIL20,160−13%

58Douglas County, ILIL19,880−0%

59Crawford County, ILIL18,648−9%

60Bond County, ILIL16,959−4%

61Hancock County, ILIL16,803−16%

62Piatt County, ILIL16,791+3%

63Union County, ILIL16,656−9%

64Edgar County, ILIL16,323−17%

65Warren County, ILIL16,222−13%

66Wayne County, ILIL15,882−7%

67Carroll County, ILIL15,419−8%

68Mercer County, ILIL15,229−10%

69Richland County, ILIL15,219−6%

70De Witt County, ILIL15,118−10%

71Clark County, ILIL15,114−11%

72Moultrie County, ILIL14,371+1%

73Pike County, ILIL14,231−18%

74Lawrence County, ILIL13,790−11%

75Washington County, ILIL13,564−10%

76Massac County, ILIL13,502−11%

77Johnson County, ILIL13,363+4%

78White County, ILIL13,250−14%

79Ford County, ILIL13,216−7%

80Clay County, ILIL12,793−12%

81Cass County, ILIL12,463−9%

82Mason County, ILIL12,411−23%

83Menard County, ILIL11,863−5%

84Marshall County, ILIL11,473−13%

85Greene County, ILIL11,313−23%

86Wabash County, ILIL10,907−16%

87Cumberland County, ILIL10,208−9%

88Jasper County, ILIL9,032−11%

89Hamilton County, ILIL7,859−9%

90Schuyler County, ILIL6,657−7%

91Brown County, ILIL6,401−8%

92Henderson County, ILIL5,984−27%

93Edwards County, ILIL5,898−15%

94Putnam County, ILIL5,619−8%

95Stark County, ILIL5,319−16%

96Scott County, ILIL4,866−12%

97Pulaski County, ILIL4,820−34%

98Gallatin County, ILIL4,616−28%

99Alexander County, ILIL4,570−52%

100Calhoun County, ILIL4,300−15%

101Pope County, ILIL3,672−17%

102Hardin County, ILIL3,588−25%

SHOWING 1–102 OF 102

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU POPULATION ESTIMATES