Illinois Population By County in 2024

Updated on June 16, 2025.

Based on the US Census Vintage data estimates, in 2024, the population of Illinois was 12,710,158. Among all Illinois counties, Cook had the highest population (5,182,617), followed by DuPage (937,142), and Lake (718,604). Hardin was the least populated county (3,550).

Hover over or click on the counties in the map below to see the populations. The data can also be found in a table below. You can use the table to sort, filter, and explore the data further.

You can see similar information for other states and by state for the United States.

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Illinois Population By County in 2024
Illinois Population By County in 2024
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County Population % of State Population
Adams 64109 0.50
Alexander 4594 0.04
Bond 16576 0.13
Boone 53313 0.42
Brown 6307 0.05
Bureau 32486 0.26
Calhoun 4224 0.03
Carroll 15444 0.12
Cass 12713 0.10
Champaign 212374 1.67
Christian 33247 0.26
Clark 15076 0.12
Clay 12821 0.10
Clinton 37087 0.29
Coles 46423 0.37
Cook 5182617 40.78
Crawford 18388 0.14
Cumberland 10305 0.08
DeKalb 101335 0.80
De Witt 15319 0.12
Douglas 19824 0.16
DuPage 937142 7.37
Edgar 16398 0.13
Edwards 5984 0.05
Effingham 34602 0.27
Fayette 21157 0.17
Ford 13451 0.11
Franklin 37033 0.29
Fulton 32510 0.26
Gallatin 4690 0.04
Greene 11417 0.09
Grundy 53835 0.42
Hamilton 7818 0.06
Hancock 17008 0.13
Hardin 3550 0.03
Henderson 6048 0.05
Henry 48177 0.38
Iroquois 26067 0.21
Jackson 53199 0.42
Jasper 9092 0.07
Jefferson 36107 0.28
Jersey 21150 0.17
Jo Daviess 21528 0.17
Johnson 13320 0.11
Kane 520997 4.10
Kankakee 106410 0.84
Kendall 143171 1.13
Knox 48716 0.38
Lake 718604 5.65
LaSalle 108390 0.85
Lawrence 14801 0.12
Lee 33544 0.26
Livingston 35375 0.28
Logan 27518 0.22
McDonough 26662 0.21
McHenry 315959 2.49
McLean 172069 1.35
Macon 100737 0.79
Macoupin 43895 0.35
Madison 263017 2.07
Marion 36437 0.29
Marshall 11552 0.09
Mason 12543 0.10
Massac 13627 0.11
Menard 11963 0.09
Mercer 15292 0.12
Monroe 34969 0.28
Montgomery 27615 0.22
Morgan 32618 0.26
Moultrie 14365 0.11
Ogle 51345 0.40
Peoria 179630 1.41
Perry 20272 0.16
Piatt 16628 0.13
Pike 14258 0.11
Pope 3703 0.03
Pulaski 4879 0.04
Putnam 5633 0.04
Randolph 29903 0.24
Richland 15362 0.12
Rock Island 142731 1.12
St. Clair 251149 1.98
Saline 22826 0.18
Sangamon 194345 1.53
Schuyler 6750 0.05
Scott 4880 0.04
Shelby 20542 0.16
Stark 5272 0.04
Stephenson 43088 0.34
Tazewell 129821 1.02
Union 16886 0.13
Vermilion 71106 0.56
Wabash 10979 0.09
Warren 16217 0.13
Washington 13535 0.11
Wayne 15928 0.13
White 13395 0.11
Whiteside 54657 0.43
Will 708583 5.58
Williamson 67064 0.53
Winnebago 283790 2.23
Woodford 38290 0.30