RANKING · 2025 ESTIMATES · 102 SHOWN OF 102

Most densely populated, Illinois counties

Illinois counties ranked by residents per square mile (2025). This list covers the 102 counties in Illinois that qualify, ranked against each other statewide.

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RELATEDLargest by population Fastest growing Fastest shrinking Most population gained Most population lost Most sparsely populated

RANKPLACESTATEPOPPOPULATION DENSITYVS –

01Cook County, ILIL5,194,6255,497–

02DuPage County, ILIL934,2982,850–

03Lake County, ILIL719,3391,622–

04Kane County, ILIL525,7571,012–

05Will County, ILIL712,253852–

06Winnebago County, ILIL283,674553–

07McHenry County, ILIL317,751527–

08Kendall County, ILIL145,470454–

09St. Clair County, ILIL250,708381–

10Madison County, ILIL263,110368–

11Rock Island County, ILIL141,869332–

12Peoria County, ILIL178,553289–

13Sangamon County, ILIL194,170224–

14Champaign County, ILIL209,972211–

15Tazewell County, ILIL130,049201–

16Boone County, ILIL53,568191–

17Macon County, ILIL99,300171–

18DeKalb County, ILIL101,835161–

19Williamson County, ILIL67,225160–

20Kankakee County, ILIL105,525156–

21McLean County, ILIL171,419145–

22Grundy County, ILIL54,052129–

23LaSalle County, ILIL107,77395–

24Coles County, ILIL46,60792–

25Monroe County, ILIL34,84090–

26Franklin County, ILIL36,91690–

27Jackson County, ILIL52,50190–

28Vermilion County, ILIL71,25979–

29Whiteside County, ILIL54,12179–

30Clinton County, ILIL37,12878–

31Stephenson County, ILIL43,22077–

32Adams County, ILIL64,26775–

33Woodford County, ILIL38,11172–

34Effingham County, ILIL34,51972–

35Ogle County, ILIL51,39968–

36Knox County, ILIL47,76767–

37Marion County, ILIL36,38264–

38Jefferson County, ILIL36,14763–

39Saline County, ILIL22,77260–

40Henry County, ILIL48,09558–

41Jersey County, ILIL21,16057–

42Morgan County, ILIL32,51557–

43Massac County, ILIL13,50257–

44Randolph County, ILIL29,92152–

45Macoupin County, ILIL43,74851–

46Wabash County, ILIL10,90749–

47Douglas County, ILIL19,88048–

48Christian County, ILIL33,44347–

49Perry County, ILIL20,16046–

50Lee County, ILIL32,91445–

51Bond County, ILIL16,95945–

52Logan County, ILIL27,18244–

53McDonough County, ILIL25,91644–

54Moultrie County, ILIL14,37143–

55Richland County, ILIL15,21942–

56Crawford County, ILIL18,64842–

57Union County, ILIL16,65640–

58Montgomery County, ILIL28,07640–

59Johnson County, ILIL13,36339–

60Piatt County, ILIL16,79138–

61De Witt County, ILIL15,11838–

62Fulton County, ILIL32,90138–

63Menard County, ILIL11,86338–

64Bureau County, ILIL32,51037–

65Lawrence County, ILIL13,79037–

66Jo Daviess County, ILIL21,59436–

67Putnam County, ILIL5,61935–

68Carroll County, ILIL15,41935–

69Livingston County, ILIL35,05734–

70Cass County, ILIL12,46333–

71Clark County, ILIL15,11430–

72Warren County, ILIL16,22230–

73Marshall County, ILIL11,47330–

74Cumberland County, ILIL10,20830–

75Fayette County, ILIL20,79029–

76Clay County, ILIL12,79327–

77Ford County, ILIL13,21627–

78Mercer County, ILIL15,22927–

79Shelby County, ILIL20,57627–

80White County, ILIL13,25027–

81Edwards County, ILIL5,89827–

82Edgar County, ILIL16,32326–

83Pulaski County, ILIL4,82024–

84Washington County, ILIL13,56424–

85Iroquois County, ILIL26,15023–

86Mason County, ILIL12,41123–

87Wayne County, ILIL15,88222–

88Hancock County, ILIL16,80321–

89Brown County, ILIL6,40121–

90Greene County, ILIL11,31321–

91Hardin County, ILIL3,58820–

92Alexander County, ILIL4,57019–

93Scott County, ILIL4,86619–

94Stark County, ILIL5,31918–

95Jasper County, ILIL9,03218–

96Hamilton County, ILIL7,85918–

97Pike County, ILIL14,23117–

98Calhoun County, ILIL4,30017–

99Henderson County, ILIL5,98416–

100Schuyler County, ILIL6,65715–

101Gallatin County, ILIL4,61614–

102Pope County, ILIL3,67210–

SHOWING 1–102 OF 102

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