Population in Illinois by County

Total population.

U.S. Census Bureau · ACS 5-year 2020-2024 · Updated November 2026

Illinois

12,694,798

Counties

102

Highest

Cook

5,182,090

Lowest

Hardin

3,605

All Illinois counties, ranked

# Counties Population
1 Cook 5,182,090
2 DuPage 930,024
3 Lake 714,223
4 Will 701,462
5 Kane 517,255
6 McHenry 312,591
7 Winnebago 283,292
8 Madison 264,238
9 St. Clair 253,694
10 Champaign 208,741
11 Sangamon 194,947
12 Peoria 179,645
13 McLean 171,556
14 Rock Island 142,757
15 Kendall 137,675
16 Tazewell 130,290
17 LaSalle 108,714
18 Kankakee 106,635
19 Macon 101,849
20 DeKalb 100,703
21 Vermilion 72,386
22 Williamson 66,876
23 Adams 64,754
24 Whiteside 54,947
25 Boone 53,230
26 Grundy 53,219
27 Jackson 53,064
28 Ogle 51,495
29 Knox 49,046
30 Henry 48,643
31 Coles 46,777
32 Macoupin 44,350
33 Stephenson 43,768
34 Woodford 38,312
35 Franklin 37,323
36 Marion 37,000
37 Clinton 36,954
38 Jefferson 36,550
39 Livingston 35,565
40 Monroe 35,036
41 Effingham 34,522
42 Lee 33,869
43 Christian 33,538
44 Morgan 33,021
45 Fulton 33,020
46 Bureau 32,866
47 Randolph 30,058
48 Montgomery 27,942
49 Logan 27,713
50 McDonough 26,920
51 Iroquois 26,449
52 Saline 23,213
53 Jo Daviess 21,851
54 Fayette 21,315
55 Jersey 21,274
56 Shelby 20,720
57 Perry 20,639
58 Douglas 19,751
59 Crawford 18,511
60 Hancock 17,281
61 Union 16,997
62 Bond 16,716
63 Piatt 16,695
64 Edgar 16,535
65 Warren 16,447
66 Wayne 15,973
67 Richland 15,598
68 Carroll 15,576
69 Mercer 15,495
70 De Witt 15,373
71 Clark 15,266
72 Lawrence 15,031
73 Pike 14,469
74 Moultrie 14,424
75 Massac 13,865
76 Washington 13,627
77 White 13,619
78 Ford 13,406
79 Johnson 13,376
80 Clay 13,052
81 Cass 12,784
82 Mason 12,745
83 Menard 12,095
84 Greene 11,683
85 Marshall 11,647
86 Wabash 11,119
87 Cumberland 10,334
88 Jasper 9,180
89 Hamilton 7,916
90 Schuyler 6,787
91 Brown 6,322
92 Henderson 6,193
93 Edwards 6,075
94 Putnam 5,601
95 Stark 5,308
96 Pulaski 5,015
97 Scott 4,937
98 Alexander 4,875
99 Gallatin 4,819
100 Calhoun 4,330
101 Pope 3,739
102 Hardin 3,605

About this dataset

Total population. Source: ACS 5-year 2020-2024 Data Profile, variable DP05_0001E. Values in people.

Source
U.S. Census Bureau
Citation
U.S. Census Bureau, American Community Survey 5-Year Estimates Data Profiles (2020-2024), DP05_0001E
Vintage
ACS 5-year 2020-2024
License
Public domain (U.S. Census Bureau)
Unit
people
Available at
State · County · ZIP code
Territory roll-up
Summed across each territory
Last loaded
November 2026

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US Population nationwide