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.

Flip the list · Most population lost, US counties →

IllinoisAll states All rankings

SAME RANKING BYCities States Metros

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION CHANGEVS 2000

01Will County, ILIL712,253+15,898−89%

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

03Kane County, ILIL525,757+9,235−89%

04McHenry 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%

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

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

10McLean County, ILIL171,419+465−98%

11Bond County, ILIL16,959+234−91%

12Clinton County, ILIL37,128+229−86%

13Brown County, ILIL6,401+157−86%

14Douglas County, ILIL19,880+140−69%

15Boone County, ILIL53,568+120−99%

16Piatt County, ILIL16,791+118−86%

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

18Johnson County, ILIL13,363+55−96%

19Putnam County, ILIL5,619-18−105%

20Crawford County, ILIL18,648-31−103%

21Hardin County, ILIL3,588-61−84%

22Stark County, ILIL5,319-81−60%

23Scott County, ILIL4,866-83−22%

24Pope County, ILIL3,672-91−328%

25Monroe County, ILIL34,840-122−102%

26Hamilton County, ILIL7,859-134−210%

27Calhoun County, ILIL4,300-137−42%

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

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

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

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

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

33Randolph County, ILIL29,921-242−65%

34Schuyler County, ILIL6,657-245−21%

35Jasper County, ILIL9,032-255−48%

36Coles County, ILIL46,607-256−116%

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

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

39Wayne County, ILIL15,882-297+230%

40Ford County, ILIL13,216-318+835%

41Gallatin County, ILIL4,616-330−29%

42Clark County, ILIL15,114-341−131%

43Edwards County, ILIL5,898-347−26%

44Jersey County, ILIL21,160-352−131%

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

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

47Ogle County, ILIL51,399-389−108%

48De Witt County, ILIL15,118-398−241%

49Morgan County, ILIL32,515-400−283%

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

51Shelby County, ILIL20,576-414−166%

52Menard County, ILIL11,863-434−133%

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

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

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

56Jackson County, ILIL52,501-473−67%

57Clay County, ILIL12,793-495−595%

58Pike County, ILIL14,231-508+163%

59Edgar County, ILIL16,323-543−598%

60Cass County, ILIL12,463-579−324%

61Union County, ILIL16,656-588−187%

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

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

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

65White County, ILIL13,250-627−46%

66Massac County, ILIL13,502-667−263%

67Alexander County, ILIL4,570-670−35%

68Greene County, ILIL11,313-672+21%

69Mason County, ILIL12,411-675+192%

70Fayette County, ILIL20,790-698−177%

71Fulton County, ILIL32,901-708−516%

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

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

74Perry County, ILIL20,160-785−147%

75Logan County, ILIL27,182-805−309%

76Hancock County, ILIL16,803-817−35%

77Franklin County, ILIL36,916-888−32%

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

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

80Saline County, ILIL22,772-996−647%

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

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

83Lee County, ILIL32,914-1,231−174%

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

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

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

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

88Adams County, ILIL64,267-1,470−167%

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

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

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

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

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

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

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

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

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

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

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

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

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

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

SHOWING 1–102 OF 102

Download CSV (full list, 102 rows)

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