Data / Rankings / Population density / Counties in Illinois

Counties in Illinois by population density

Cook County had the highest population density of 102 counties in 2023, at 2,101.4 inhabitants per km². Pope County had the lowest, at 3.9 inhabitants per km². The median was 17.2 inhabitants per km² and the figure for Illinois was 87.9 inhabitants per km². Source: the U.S. Census Bureau.

Highest2,101.4Cook County
Lowest3.9Pope County
Median17.2102 counties
Illinois87.9History

Top 40 counties, 2023

CSVChart (SVG)

Cook CountyCook County: 2,101.4 inhabitants per km²2,101.4DuPage CountyDuPage County: 1,092 inhabitants per km²1,092Lake CountyLake County: 621 inhabitants per km²621Kane CountyKane County: 385.3 inhabitants per km²385.3Will CountyWill County: 325.1 inhabitants per km²325.1Winnebago CountyWinnebago County: 212 inhabitants per km²212McHenry CountyMcHenry County: 200.6 inhabitants per km²200.6Kendall CountyKendall County: 169.1 inhabitants per km²169.1St. Clair CountySt. Clair County: 148.1 inhabitants per km²148.1Madison CountyMadison County: 142.1 inhabitants per km²142.1Rock Island CountyRock Island County: 127.3 inhabitants per km²127.3Peoria CountyPeoria County: 111.1 inhabitants per km²111.1Sangamon CountySangamon County: 86.3 inhabitants per km²86.3Champaign CountyChampaign County: 80.8 inhabitants per km²80.8Tazewell CountyTazewell County: 77.7 inhabitants per km²77.7Boone CountyBoone County: 73.4 inhabitants per km²73.4Macon CountyMacon County: 66.7 inhabitants per km²66.7Williamson CountyWilliamson County: 61.3 inhabitants per km²61.3DeKalb CountyDeKalb County: 61.2 inhabitants per km²61.2Kankakee CountyKankakee County: 60.4 inhabitants per km²60.4McLean CountyMcLean County: 55.8 inhabitants per km²55.8Grundy CountyGrundy County: 49.4 inhabitants per km²49.4LaSalle CountyLaSalle County: 36.7 inhabitants per km²36.7Coles CountyColes County: 35.5 inhabitants per km²35.5Monroe CountyMonroe County: 35.3 inhabitants per km²35.3Franklin CountyFranklin County: 35 inhabitants per km²35Jackson CountyJackson County: 34.7 inhabitants per km²34.7Vermilion CountyVermilion County: 30.8 inhabitants per km²30.8Whiteside CountyWhiteside County: 30.7 inhabitants per km²30.7Clinton CountyClinton County: 30.1 inhabitants per km²30.1Stephenson CountyStephenson County: 29.8 inhabitants per km²29.8Adams CountyAdams County: 29.1 inhabitants per km²29.1Woodford CountyWoodford County: 28 inhabitants per km²28Effingham CountyEffingham County: 27.8 inhabitants per km²27.8Ogle CountyOgle County: 26.1 inhabitants per km²26.1Knox CountyKnox County: 26 inhabitants per km²26Marion CountyMarion County: 24.7 inhabitants per km²24.7Jefferson CountyJefferson County: 24.5 inhabitants per km²24.5Saline CountySaline County: 23.3 inhabitants per km²23.3Henry CountyHenry County: 22.7 inhabitants per km²22.7
inhabitants per km². Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09.

Full ranking

RankCounties2023
inhabitants per km²		Change on 2022
1Cook County2,101.4+0.3%
2DuPage County1,092+0.3%
3Lake County621+0.2%
4Kane County385.3+0.6%
5Will County325.1+0.7%
6Winnebago County212-0%
7McHenry County200.6+0.5%
8Kendall County169.1+1.9%
9St. Clair County148.1-0.2%
10Madison County142.1-0.2%
11Rock Island County127.3-0%
12Peoria County111.1-0.1%
13Sangamon County86.3-0.1%
14Champaign County80.8+0.2%
15Tazewell County77.7+0.1%
16Boone County73.4+0.5%
17Macon County66.7-0.8%
18Williamson County61.3+0.3%
19DeKalb County61.2-0.1%
20Kankakee County60.4-0%
21McLean County55.8-0.1%
22Grundy County49.4+0.8%
23LaSalle County36.7+0.1%
24Coles County35.5-0.1%
25Monroe County35.3+0.2%
26Franklin County35-0.2%
27Jackson County34.7-0.4%
28Vermilion County30.8-0.6%
29Whiteside County30.7-0.1%
30Clinton County30.1-0.3%
31Stephenson County29.8-0.5%
32Adams County29.1-0.1%
33Woodford County28+0.2%
34Effingham County27.8+0.4%
35Ogle County26.1-0.1%
36Knox County26-1%
37Marion County24.7-0.5%
38Jefferson County24.5-0.4%
39Saline County23.3-0.7%
40Henry County22.7-0.5%
41Massac County22.4-0.9%
42Morgan County22.3-0.7%
43Jersey County22.1-0.3%
44Randolph County20-0.5%
45Macoupin County19.7-0.3%
46Wabash County19.10%
47Douglas County18.3+0.4%
48Christian County18.2-0.3%
49Perry County18.1+0.2%
50McDonough County17.6+0.1%
51Lee County17.5-1.6%
52Bond County16.9-0.4%
53Logan County16.9-0.6%
54Richland County16.6-0.1%
55Moultrie County16.5-0.1%
56Crawford County16-0.1%
57Union County15.8-0.3%
58Montgomery County15.2-0.6%
59Johnson County15-0.2%
60De Witt County14.9-0.2%
61Menard County14.7-0.5%
62Piatt County14.7+0.3%
63Fulton County14.7-0.9%
64Bureau County14.5-0.3%
65Lawrence County14.2+0.5%
66Jo Daviess County14-0.3%
67Carroll County13.5-0.1%
68Putnam County13.5+0.4%
69Cass County13.1+0.5%
70Livingston County13-0.9%
71Clark County11.7+0.1%
72Marshall County11.60%
73Warren County11.5-0.7%
74Cumberland County11.5-0.2%
75Fayette County11.3-0.4%
76Clay County10.7-0.8%
77Mercer County10.6-0.3%
78Ford County10.6+0.1%
79White County10.5-1%
80Shelby County10.5-0.6%
81Edwards County10.5-0.7%
82Edgar County10.20%
83Pulaski County9.6+0.1%
84Washington County9.3-0.6%
85Iroquois County9-1.1%
86Mason County9-1%
87Wayne County8.6-0.2%
88Hancock County8.4-0.4%
89Greene County8.2-0.6%
90Brown County8.2+0.9%
91Hardin County7.9+0.5%
92Alexander County7.8-2.7%
93Scott County7.5-0.6%
94Jasper County7.1-0.3%
95Stark County7.1-1%
96Hamilton County7-1.1%
97Pike County6.7-1.3%
98Calhoun County6.6-0%
99Henderson County6.2-1%
100Schuyler County5.9-0.6%
101Gallatin County5.6-2.8%
102Pope County3.9-1.2%

Other periods

About this ranking

Resident population divided by land area in km². World Bank figures use mid-year population and land area excluding inland water.

United States: Census Bureau population estimates for 1 July divided by land area (water excluded) from the latest Census Gazetteer files. US tables often give people per square mile; multiply persons per km² by 2.59 to compare.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-09.

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Rank Counties in Illinois by population density using official data, and cite the source.
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Questions

Which county has the highest population density?

Cook County, with 2,101.4 inhabitants per km² in 2023, according to the U.S. Census Bureau.

Which county has the lowest population density?

Pope County, with 3.9 inhabitants per km² in 2023.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². Retrieved 2026-10-09.

Population density: other rankings

Counties in Illinois: more rankings