Illinois Population By County in 2019

Updated on January 29, 2024.

Based on the US Census Vintage data estimates, in 2019, the population of Illinois was 12,667,017. Among all Illinois counties, Cook[object Promise] had the highest population (5,145,326), followed by DuPage[object Promise] (922,761), and Lake[object Promise] (697,134). Hardin[object Promise] was the least populated county (3,848).

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 2019
Illinois Population By County in 2019
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County Population % of State Population
Adams 65402 0.52
Alexander 5791 0.05
Bond 16458 0.13
Boone 53281 0.42
Brown 6619 0.05
Bureau 32621 0.26
Calhoun 4740 0.04
Carroll 14338 0.11
Cass 12141 0.10
Champaign 209612 1.66
Christian 32427 0.26
Clark 15465 0.12
Clay 13177 0.10
Clinton 37440 0.30
Coles 50774 0.40
Cook 5145326 40.62
Crawford 18686 0.15
Cumberland 10733 0.09
DeKalb 105131 0.83
De Witt 15624 0.12
Douglas 19450 0.15
DuPage 922761 7.29
Edgar 17169 0.14
Edwards 6405 0.05
Effingham 34109 0.27
Fayette 21332 0.17
Ford 12972 0.10
Franklin 38530 0.30
Fulton 34240 0.27
Gallatin 4833 0.04
Greene 12922 0.10
Grundy 51031 0.40
Hamilton 8133 0.06
Hancock 17700 0.14
Hardin 3848 0.03
Henderson 6709 0.05
Henry 48933 0.39
Iroquois 27093 0.21
Jackson 56844 0.45
Jasper 9618 0.08
Jefferson 37635 0.30
Jersey 21667 0.17
Jo Daviess 21224 0.17
Johnson 12380 0.10
Kane 532293 4.20
Kankakee 109569 0.87
Kendall 128900 1.02
Knox 49669 0.39
Lake 697134 5.50
LaSalle 108517 0.86
Lawrence 15665 0.12
Lee 34061 0.27
Livingston 35557 0.28
Logan 28633 0.23
McDonough 29792 0.24
McHenry 307439 2.43
McLean 171272 1.35
Macon 104012 0.82
Macoupin 45079 0.36
Madison 263609 2.08
Marion 37309 0.30
Marshall 11463 0.09
Mason 13387 0.11
Massac 13772 0.11
Menard 12198 0.10
Mercer 15490 0.12
Monroe 34738 0.27
Montgomery 28401 0.22
Morgan 33679 0.27
Moultrie 14464 0.11
Ogle 50660 0.40
Peoria 179359 1.42
Perry 20935 0.17
Piatt 16391 0.13
Pike 15574 0.12
Pope 4176 0.03
Pulaski 5309 0.04
Putnam 5745 0.05
Randolph 31725 0.25
Richland 15519 0.12
Rock Island 141775 1.12
St. Clair 259889 2.05
Saline 23540 0.19
Sangamon 194882 1.54
Schuyler 6829 0.05
Scott 4974 0.04
Shelby 21625 0.17
Stark 5312 0.04
Stephenson 44371 0.35
Tazewell 131848 1.04
Union 16693 0.13
Vermilion 75736 0.60
Wabash 11370 0.09
Warren 16816 0.13
Washington 13926 0.11
Wayne 16196 0.13
White 13574 0.11
Whiteside 55215 0.44
Will 690176 5.45
Williamson 66633 0.53
Winnebago 282465 2.23
Woodford 38353 0.30