RANKING · 2010 CENSUS · 102 SHOWN OF 102

Most densely populated, Illinois counties · 2010

Illinois counties ranked by residents per square mile (2023). This list covers the 102 counties in Illinois that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest growing Fastest shrinking Most sparsely populated Best broadband access Worst broadband access

YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS 2000

01Cook County, ILIL5,194,6255,497−3%

02DuPage County, ILIL934,2982,797+1%

03Lake County, ILIL719,3391,586+9%

04Kane County, ILIL525,757992+28%

05Will County, ILIL712,253811+35%

06Winnebago County, ILIL283,674576+6%

07McHenry County, ILIL317,751512+19%

08St. Clair County, ILIL250,708411+5%

09Madison County, ILIL263,110376+4%

10Kendall County, ILIL145,470358+110%

11Rock Island County, ILIL141,869345−1%

12Peoria County, ILIL178,553301+2%

13Sangamon County, ILIL194,170227+5%

14Tazewell County, ILIL130,049209+5%

15Champaign County, ILIL209,972202+12%

16Boone County, ILIL53,568193+30%

17Macon County, ILIL99,300191−3%

18Kankakee County, ILIL105,525168+9%

19DeKalb County, ILIL101,835167+18%

20Williamson County, ILIL67,225158+8%

21McLean County, ILIL171,419143+13%

22Grundy County, ILIL54,052120+33%

23Coles County, ILIL46,607106+1%

24Jackson County, ILIL52,501103+1%

25LaSalle County, ILIL107,773100+2%

26Franklin County, ILIL36,91697+1%

27Vermilion County, ILIL71,25991−3%

28Monroe County, ILIL34,84086+19%

29Whiteside County, ILIL54,12186−4%

30Stephenson County, ILIL43,22085−3%

31Clinton County, ILIL37,12880+6%

32Adams County, ILIL64,26778−2%

33Knox County, ILIL47,76774−5%

34Woodford County, ILIL38,11173+9%

35Effingham County, ILIL34,51972−0%

36Ogle County, ILIL51,39971+5%

37Marion County, ILIL36,38269−5%

38Jefferson County, ILIL36,14768−3%

39Saline County, ILIL22,77266−7%

40Massac County, ILIL13,50265+2%

41Morgan County, ILIL32,51562−3%

42Jersey County, ILIL21,16062+6%

43Henry County, ILIL48,09561−1%

44Randolph County, ILIL29,92158−1%

45Macoupin County, ILIL43,74855−3%

46McDonough County, ILIL25,91655−1%

47Wabash County, ILIL10,90753−8%

48Perry County, ILIL20,16051−3%

49Lee County, ILIL32,91450−0%

50Christian County, ILIL33,44349−2%

51Logan County, ILIL27,18249−3%

52Douglas County, ILIL19,88048+0%

53Bond County, ILIL16,95947+1%

54Lawrence County, ILIL13,79045+9%

55Richland County, ILIL15,21945+1%

56Crawford County, ILIL18,64845−3%

57Moultrie County, ILIL14,37144+4%

58Union County, ILIL16,65643−3%

59Fulton County, ILIL32,90143−3%

60Montgomery County, ILIL28,07643−2%

61De Witt County, ILIL15,11842−1%

62Menard County, ILIL11,86340+2%

63Bureau County, ILIL32,51040−1%

64Piatt County, ILIL16,79138+2%

65Jo Daviess County, ILIL21,59438+2%

66Putnam County, ILIL5,61938−1%

67Livingston County, ILIL35,05737−2%

68Johnson County, ILIL13,36337−2%

69Cass County, ILIL12,46336−0%

70Alexander County, ILIL4,57035−14%

71Carroll County, ILIL15,41935−8%

72Marshall County, ILIL11,47333−4%

73Warren County, ILIL16,22233−5%

74Clark County, ILIL15,11433−4%

75Cumberland County, ILIL10,20832−2%

76Pulaski County, ILIL4,82031−16%

77Fayette County, ILIL20,79031+2%

78Edwards County, ILIL5,89830−4%

79Edgar County, ILIL16,32330−6%

80White County, ILIL13,25030−5%

81Clay County, ILIL12,79329−5%

82Shelby County, ILIL20,57629−2%

83Mercer County, ILIL15,22929−3%

84Ford County, ILIL13,21629−1%

85Mason County, ILIL12,41127−9%

86Iroquois County, ILIL26,15027−5%

87Washington County, ILIL13,56426−3%

88Greene County, ILIL11,31326−6%

89Hardin County, ILIL3,58824−10%

90Hancock County, ILIL16,80324−5%

91Wayne County, ILIL15,88223−2%

92Brown County, ILIL6,40123−0%

93Scott County, ILIL4,86621−3%

94Stark County, ILIL5,31921−5%

95Calhoun County, ILIL4,30020+0%

96Pike County, ILIL14,23120−5%

97Jasper County, ILIL9,03220−4%

98Hamilton County, ILIL7,85919−2%

99Henderson County, ILIL5,98419−11%

100Gallatin County, ILIL4,61617−13%

101Schuyler County, ILIL6,65717+5%

102Pope County, ILIL3,67212+1%

SHOWING 1–102 OF 102

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