# Counties in Illinois by population density, 2025

All 102 values come from U.S. Census Bureau for 2025, so the places are comparable.

- Indicator id: `population_density`
- Unit: inhabitants per km²
- Definition: Resident population divided by land area in km². World Bank figures use mid-year population and land area excluding inland water.
- Source: 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
- Citation: 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.
- Web page: https://invokely.ai/rankings/population-density/illinois-counties
- CSV: https://invokely.ai/download/rankings/population-density/illinois-counties.csv

| Rank | Place | inhabitants per km² |
|---:|---|---:|
| 1 | Cook County | 2,122.5 |
| 2 | DuPage County | 1,100.1 |
| 3 | Lake County | 626 |
| 4 | Kane County | 390.9 |
| 5 | Will County | 329 |
| 6 | Winnebago County | 213.5 |
| 7 | McHenry County | 203.3 |
| 8 | Kendall County | 175.4 |
| 9 | St. Clair County | 147.2 |
| 10 | Madison County | 142 |
| 11 | Rock Island County | 128.1 |
| 12 | Peoria County | 111.4 |
| 13 | Sangamon County | 86.3 |
| 14 | Champaign County | 81.4 |
| 15 | Tazewell County | 77.7 |
| 16 | Boone County | 73.7 |
| 17 | Macon County | 66 |
| 18 | DeKalb County | 62.3 |
| 19 | Williamson County | 61.8 |
| 20 | Kankakee County | 60.2 |
| 21 | McLean County | 55.9 |
| 22 | Grundy County | 49.9 |
| 23 | LaSalle County | 36.7 |
| 24 | Coles County | 35.4 |
| 25 | Monroe County | 34.9 |
| 26 | Franklin County | 34.9 |
| 27 | Jackson County | 34.7 |
| 28 | Vermilion County | 30.6 |
| 29 | Whiteside County | 30.5 |
| 30 | Clinton County | 30.2 |
| 31 | Stephenson County | 29.6 |
| 32 | Adams County | 29 |
| 33 | Woodford County | 27.9 |
| 34 | Effingham County | 27.8 |
| 35 | Ogle County | 26.2 |
| 36 | Knox County | 25.7 |
| 37 | Marion County | 24.5 |
| 38 | Jefferson County | 24.4 |
| 39 | Saline County | 23.1 |
| 40 | Henry County | 22.6 |
| 41 | Jersey County | 22.1 |
| 42 | Morgan County | 22.1 |
| 43 | Massac County | 22 |
| 44 | Randolph County | 20.1 |
| 45 | Macoupin County | 19.6 |
| 46 | Wabash County | 18.9 |
| 47 | Douglas County | 18.4 |
| 48 | Christian County | 18.2 |
| 49 | Perry County | 17.6 |
| 50 | Lee County | 17.5 |
| 51 | Bond County | 17.2 |
| 52 | Logan County | 17 |
| 53 | McDonough County | 17 |
| 54 | Moultrie County | 16.5 |
| 55 | Richland County | 16.3 |
| 56 | Crawford County | 16.2 |
| 57 | Union County | 15.6 |
| 58 | Montgomery County | 15.4 |
| 59 | Johnson County | 15 |
| 60 | Piatt County | 14.8 |
| 61 | De Witt County | 14.7 |
| 62 | Fulton County | 14.7 |
| 63 | Menard County | 14.6 |
| 64 | Bureau County | 14.4 |
| 65 | Lawrence County | 14.3 |
| 66 | Jo Daviess County | 13.9 |
| 67 | Putnam County | 13.6 |
| 68 | Carroll County | 13.4 |
| 69 | Livingston County | 13 |
| 70 | Cass County | 12.8 |
| 71 | Clark County | 11.6 |
| 72 | Warren County | 11.5 |
| 73 | Marshall County | 11.5 |
| 74 | Cumberland County | 11.4 |
| 75 | Fayette County | 11.2 |
| 76 | Clay County | 10.5 |
| 77 | Ford County | 10.5 |
| 78 | Mercer County | 10.5 |
| 79 | Shelby County | 10.5 |
| 80 | White County | 10.3 |
| 81 | Edwards County | 10.2 |
| 82 | Edgar County | 10.1 |
| 83 | Pulaski County | 9.3 |
| 84 | Washington County | 9.3 |
| 85 | Iroquois County | 9 |
| 86 | Mason County | 8.9 |
| 87 | Wayne County | 8.6 |
| 88 | Hancock County | 8.2 |
| 89 | Brown County | 8.1 |
| 90 | Greene County | 8 |
| 91 | Hardin County | 7.8 |
| 92 | Alexander County | 7.5 |
| 93 | Scott County | 7.5 |
| 94 | Stark County | 7.1 |
| 95 | Jasper County | 7.1 |
| 96 | Hamilton County | 7 |
| 97 | Pike County | 6.6 |
| 98 | Calhoun County | 6.5 |
| 99 | Henderson County | 6.1 |
| 100 | Schuyler County | 5.9 |
| 101 | Gallatin County | 5.5 |
| 102 | Pope County | 3.8 |