Illinois Counties by Population (2025)

by Kristen Carney Kristen Carney

Updated: December 17, 2024

The most populous counties in Illinois are Cook County with 5,087,072, DuPage County at 921,213, Lake County with 708,760, Will County at 700,728, and Kane County with 514,982. You can get the most current Census population data for all 102 Illinois counties, sorted from the most populous counties in Illinois to the least, according to the 2023 Population Estimates Program.

Sure, you can copy this list right into your favorite spreadsheet tool. Or save yourself formatting headaches and grab the latest Illinois counties population data as a ready-to-use Excel™ file below. It's time to stop searching and start digging into data!

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Rank County Population
1 Cook County 5,087,072
2 DuPage County 921,213
3 Lake County 708,760
4 Will County 700,728
5 Kane County 514,982
6 McHenry County 312,800
7 Winnebago County 280,922
8 Madison County 262,752
9 St. Clair County 251,018
10 Champaign County 205,644
11 Sangamon County 193,491
12 Peoria County 177,513
13 McLean County 170,441
14 Rock Island County 141,236
15 Kendall County 139,976
16 Tazewell County 129,541
17 LaSalle County 108,309
18 Kankakee County 105,940
19 Macon County 100,591
20 DeKalb County 100,288
21 Vermilion County 71,652
22 Williamson County 66,706
23 Adams County 64,441
24 Whiteside County 54,498
25 Grundy County 53,578
26 Boone County 53,202
27 Jackson County 52,141
28 Ogle County 51,265
29 Henry County 48,448
30 Knox County 48,411
31 Coles County 46,060
32 Macoupin County 44,018
33 Stephenson County 43,105
34 Woodford County 38,285
35 Franklin County 37,138
36 Clinton County 36,785
37 Marion County 36,673
38 Jefferson County 36,320
39 Livingston County 35,320
40 Monroe County 34,957
41 Effingham County 34,331
42 Lee County 33,654
43 Christian County 33,228
44 Bureau County 32,729
45 Fulton County 32,541
46 Morgan County 32,140
47 Randolph County 29,815
48 Montgomery County 27,663
49 Logan County 27,590
50 McDonough County 26,839
51 Iroquois County 26,136
52 Saline County 22,873
53 Jo Daviess County 21,756
54 Fayette County 21,164
55 Jersey County 21,091
56 Shelby County 20,568
57 Perry County 20,503
58 Douglas County 19,629
59 Crawford County 18,300
60 Hancock County 17,186
61 Piatt County 16,714
62 Union County 16,667
63 Bond County 16,450
64 Edgar County 16,334
65 Warren County 16,185
66 Wayne County 15,761
67 Carroll County 15,526
68 Richland County 15,488
69 Mercer County 15,487
70 De Witt County 15,365
71 Clark County 15,088
72 Lawrence County 14,813
73 TIE Pike County 14,342
73 TIE Moultrie County 14,342
75 Massac County 13,661
76 Washington County 13,536
77 White County 13,401
78 Johnson County 13,326
79 Ford County 13,250
80 Clay County 12,999
81 Cass County 12,596
82 Mason County 12,523
83 Menard County 11,954
84 Marshall County 11,683
85 Greene County 11,543
86 Wabash County 10,942
87 Cumberland County 10,261
88 Jasper County 9,144
89 Hamilton County 7,911
90 Schuyler County 6,733
91 Brown County 6,294
92 Henderson County 6,088
93 Edwards County 5,968
94 Putnam County 5,561
95 Stark County 5,218
96 Pulaski County 4,911
97 Scott County 4,710
98 Alexander County 4,695
99 Gallatin County 4,670
100 Calhoun County 4,317
101 Pope County 3,707
102 Hardin County 3,569

United States Census Bureau. Annual Estimates of the Resident Population: April 1, 2020 to July 1, 2023. Population Division. May 2024.

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