RANKING · 2025 ESTIMATES · 102 SHOWN OF 102

Most population gained, Illinois counties

Illinois counties that added the most residents from the 2020 census to 2025, by raw count of people rather than percentage. This list covers the 102 counties in Illinois that qualify, ranked against each other statewide. The median across all 102 is -414. Biggest climber in the top 100 since 2020: DeKalb County, IL, up 85 places to #9.

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IllinoisAll states All rankings

SAME RANKING BYCities States Metros

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION CHANGEVS 2000

01▲1Will County, ILIL712,253+15,898−89%

02▲1Kendall County, ILIL145,470+13,601−10%

03▲8Kane County, ILIL525,757+9,235−89%

04▲5McHenry County, ILIL317,751+7,522−90%

05Lake County, ILIL719,339+4,997−96%

06Champaign County, ILIL209,972+4,107−38%

07Grundy County, ILIL54,052+1,519−71%

08▼4DuPage County, ILIL934,298+1,421−99%

09▲85DeKalb County, ILIL101,835+1,415−87%

10McLean County, ILIL171,419+465−98%

11▲43Bond County, ILIL16,959+234−91%

12▲35Clinton County, ILIL37,128+229−86%

13▲28Brown County, ILIL6,401+157−86%

14▲4Douglas County, ILIL19,880+140−69%

15▲28Boone County, ILIL53,568+120−99%

16Piatt County, ILIL16,791+118−86%

17▼5Williamson County, ILIL67,225+72−98%

18▼5Johnson County, ILIL13,363+55−96%

19▲1Putnam County, ILIL5,619-18−105%

20▲37Crawford County, ILIL18,648-31−103%

21▲19Hardin County, ILIL3,588-61−84%

22▲10Stark County, ILIL5,319-81−60%

23▼2Scott County, ILIL4,866-83−22%

24▲18Pope County, ILIL3,672-91−328%

25▼17Monroe County, ILIL34,840-122−102%

26▼1Hamilton County, ILIL7,859-134−210%

27▲11Calhoun County, ILIL4,300-137−42%

28▼14Effingham County, ILIL34,519-149−106%

29▼10Moultrie County, ILIL14,371-155−143%

30▲22Washington County, ILIL13,564-197−208%

31▲44Montgomery County, ILIL28,076-212+179%

32▲1Cumberland County, ILIL10,208-242−142%

33▲55Randolph County, ILIL29,921-242−65%

34▲1Schuyler County, ILIL6,657-245−21%

35▼12Jasper County, ILIL9,032-255−48%

36▲62Coles County, ILIL46,607-256−116%

37▲13Marshall County, ILIL11,473-269−181%

38▼23Carroll County, ILIL15,419-283+116%

39▼9Wayne County, ILIL15,882-297+230%

40▼12Ford County, ILIL13,216-318+835%

41▼5Gallatin County, ILIL4,616-330−29%

42▲7Clark County, ILIL15,114-341−131%

43▼17Edwards County, ILIL5,898-347−26%

44▲20Jersey County, ILIL21,160-352−131%

45▼28Woodford County, ILIL38,111-356−113%

46▲7Pulaski County, ILIL4,820-373+113%

47▲23Ogle County, ILIL51,399-389−108%

48▲7De Witt County, ILIL15,118-398−241%

49▲30Morgan County, ILIL32,515-400−283%

50▲1Henderson County, ILIL5,984-403−444%

51▲11Shelby County, ILIL20,576-414−166%

52▼30Menard County, ILIL11,863-434−133%

53▼16Jo Daviess County, ILIL21,594-441−194%

54▼23Wabash County, ILIL10,907-454+161%

55▼11Mercer County, ILIL15,229-470+41%

56▲43Jackson County, ILIL52,501-473−67%

57▼30Clay County, ILIL12,793-495−595%

58▲10Pike County, ILIL14,231-508+163%

59▲12Edgar County, ILIL16,323-543−598%

60▼26Cass County, ILIL12,463-579−324%

61▼32Union County, ILIL16,656-588−187%

62▼17Christian County, ILIL33,443-589−162%

63▼39Richland County, ILIL15,219-594+50%

64▼16Warren County, ILIL16,222-613+37%

65▼19White County, ILIL13,250-627−46%

66▼6Massac County, ILIL13,502-667−263%

67▲18Alexander County, ILIL4,570-670−35%

68▲9Greene County, ILIL11,313-672+21%

69▼2Mason County, ILIL12,411-675+192%

70▼31Fayette County, ILIL20,790-698−177%

71▲19Fulton County, ILIL32,901-708−516%

72▲1Bureau County, ILIL32,510-734+297%

73▲14Livingston County, ILIL35,057-758−301%

74▼11Perry County, ILIL20,160-785−147%

75▲3Logan County, ILIL27,182-805−309%

76▼11Hancock County, ILIL16,803-817−35%

77▼3Franklin County, ILIL36,916-888−32%

78▲2Iroquois County, ILIL26,150-927−269%

79▼7Jefferson County, ILIL36,147-966−132%

80▼22Saline County, ILIL22,772-996−647%

81▼22Henry County, ILIL48,095-1,189+755%

82▼1Macoupin County, ILIL43,748-1,219−191%

83▼7Lee County, ILIL32,914-1,231−174%

84▲7Tazewell County, ILIL130,049-1,294−127%

85▲10McDonough County, ILIL25,916-1,322−43%

86▼17Marion County, ILIL36,382-1,347−1136%

87▼1Stephenson County, ILIL43,220-1,410−252%

88▼27Adams County, ILIL64,267-1,470−167%

89▼23Lawrence County, ILIL13,790-1,490+187%

90▼8Whiteside County, ILIL54,121-1,570−436%

91▲10Winnebago County, ILIL283,674-1,676−107%

92LaSalle County, ILIL107,773-1,885−141%

93▲3Kankakee County, ILIL105,525-1,977−126%

94▼38Sangamon County, ILIL194,170-2,173−121%

95▼11Knox County, ILIL47,767-2,200+295%

96▼7Madison County, ILIL263,110-2,749−128%

97▼14Rock Island County, ILIL141,869-2,803−531%

98▲2Vermilion County, ILIL71,259-2,929−32%

99▼6Peoria County, ILIL178,553-3,277−641%

100▼3Macon County, ILIL99,300-4,698+88%

101▲1St. Clair County, ILIL250,708-6,692−1%

102▼101Cook County, ILIL5,194,625-80,916−130%

SHOWING 1–102 OF 102

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