RANKING · 2020 CENSUS · 102 SHOWN OF 102

Most population gained, Illinois counties · 2020

Illinois counties that added the most residents from the 2010 census to 2020, by raw count of people rather than percentage. This list covers the 102 counties in Illinois that qualify, ranked against each other statewide.

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IllinoisAll states All rankings

SAME RANKING BYCities States Metros

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION CHANGEVS 2000

01Cook County, ILIL5,194,625+80,866−70%

02Will County, ILIL712,253+18,795−87%

03Kendall County, ILIL145,470+17,133+13%

04DuPage County, ILIL934,298+15,953−87%

05Lake County, ILIL719,339+10,880−91%

06Champaign County, ILIL209,972+4,784−28%

07Grundy County, ILIL54,052+2,470−52%

08Monroe County, ILIL34,840+2,005−61%

09McHenry County, ILIL317,751+1,469−98%

10McLean County, ILIL171,419+1,382−93%

11Kane County, ILIL525,757+1,253−99%

12Williamson County, ILIL67,225+796−78%

13Johnson County, ILIL13,363+726−53%

14Effingham County, ILIL34,519+426−83%

15Carroll County, ILIL15,419+315−340%

16Piatt County, ILIL16,791-56−107%

17Woodford County, ILIL38,111-197−107%

18Douglas County, ILIL19,880-240−152%

19Moultrie County, ILIL14,371-320−190%

20Putnam County, ILIL5,619-369−204%

21Scott County, ILIL4,866-406+279%

22Menard County, ILIL11,863-408−131%

23Jasper County, ILIL9,032-411−16%

24Richland County, ILIL15,219-420+6%

25Hamilton County, ILIL7,859-464−480%

26Edwards County, ILIL5,898-476+1%

27Clay County, ILIL12,793-527−627%

28Ford County, ILIL13,216-547+1509%

29Union County, ILIL16,656-564−184%

30Wayne County, ILIL15,882-581+546%

31Wabash County, ILIL10,907-586+237%

32Stark County, ILIL5,319-594+194%

33Cumberland County, ILIL10,208-598−203%

34Cass County, ILIL12,463-600−333%

35Schuyler County, ILIL6,657-642+108%

36Gallatin County, ILIL4,616-643+39%

37Jo Daviess County, ILIL21,594-643−237%

38Calhoun County, ILIL4,300-652+174%

39Fayette County, ILIL20,790-652−172%

40Hardin County, ILIL3,588-671+72%

41Brown County, ILIL6,401-693−162%

42Pope County, ILIL3,672-707−1868%

43Boone County, ILIL53,568-717−107%

44Mercer County, ILIL15,229-735+121%

45Christian County, ILIL33,443-768−181%

46White County, ILIL13,250-788−32%

47Clinton County, ILIL37,128-863−154%

48Warren County, ILIL16,222-872+96%

49Clark County, ILIL15,114-880−181%

50Marshall County, ILIL11,473-898−369%

51Henderson County, ILIL5,984-944−907%

52Washington County, ILIL13,564-955−622%

53Pulaski County, ILIL4,820-968+453%

54Bond County, ILIL16,959-1,043−139%

55De Witt County, ILIL15,118-1,045−471%

56Sangamon County, ILIL194,170-1,122−111%

57Crawford County, ILIL18,648-1,138−215%

58Saline County, ILIL22,772-1,145−729%

59Henry County, ILIL48,095-1,202+765%

60Massac County, ILIL13,502-1,260−408%

61Adams County, ILIL64,267-1,366−162%

62Shelby County, ILIL20,576-1,373−317%

63Perry County, ILIL20,160-1,405−184%

64Jersey County, ILIL21,160-1,473−230%

65Hancock County, ILIL16,803-1,484+19%

66Lawrence County, ILIL13,790-1,553+199%

67Mason County, ILIL12,411-1,580+584%

68Pike County, ILIL14,231-1,691+776%

69Marion County, ILIL36,382-1,708−1414%

70Ogle County, ILIL51,399-1,709−134%

71Edgar County, ILIL16,323-1,710−1669%

72Jefferson County, ILIL36,147-1,714−157%

73Bureau County, ILIL32,510-1,734+837%

74Franklin County, ILIL36,916-1,757+35%

75Montgomery County, ILIL28,076-1,816+2289%

76Lee County, ILIL32,914-1,886−213%

77Greene County, ILIL11,313-1,901+242%

78Logan County, ILIL27,182-2,318−702%

79Morgan County, ILIL32,515-2,632−1302%

80Iroquois County, ILIL26,150-2,641−583%

81Macoupin County, ILIL43,748-2,798−309%

82Whiteside County, ILIL54,121-2,807−701%

83Rock Island County, ILIL141,869-2,874−541%

84Knox County, ILIL47,767-2,952+430%

85Alexander County, ILIL4,570-2,998+189%

86Stephenson County, ILIL43,220-3,081−432%

87Livingston County, ILIL35,057-3,135−932%

88Randolph County, ILIL29,921-3,313+380%

89Madison County, ILIL263,110-3,423−135%

90Fulton County, ILIL32,901-3,460−2135%

91Tazewell County, ILIL130,049-4,051−185%

92LaSalle County, ILIL107,773-4,266−193%

93Peoria County, ILIL178,553-4,664−870%

94DeKalb County, ILIL101,835-4,740−143%

95McDonough County, ILIL25,916-5,374+131%

96Kankakee County, ILIL105,525-5,947−178%

97Macon County, ILIL99,300-6,770+171%

98Coles County, ILIL46,607-7,010−552%

99Jackson County, ILIL52,501-7,244+398%

100Vermilion County, ILIL71,259-7,437+71%

101Winnebago County, ILIL283,674-9,916−139%

102St. Clair County, ILIL250,708-12,656+87%

SHOWING 1–102 OF 102

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU DECENNIAL CENSUS