Illinois counties by population provide a detailed snapshot based on the 2020 census data of the United States. There are 102 counties in Illinois that accommodate 12,812,508 residents, which is 4% of the total population in the United States. With 37.70%, Kansas has the higher education rate than the national average 35.7%. When it comes to employment rate and household income, Illinois offers the best employment rate than the national average, with $76,708 median household income.
To know more about Illinois population by county, choose any county of Illinois tells what is the total population, how dense is the population per square miles, how much population access the education, what percent of population employed, what is the median household income, what percent of population covered by health insurance and how many housing units available, in that specific county compared with Illinois (state level) and United States (nation level) population data. Similarly, the city based population details can be accessed at Illinois Cities by Population.
Which is the most populous county in Illinois?
Cook County in Illinois, USA, is the most populous county, with a resident population of 5,275,541 according to the 2020 US census data. With a 932,877 resident population DuPage County, IL ranks as the second most populated county in the state. Lake County with a population of 714,342 residents claims the third largest county by population in Illinois.
Which is the least populous county in Illinois
Hardin County with a population of 3,649 residents, is recognized as the smallest county in Illinois by population.
Illinois Counties by Population
| Rank | County | Population |
|---|
| 1 | Cook County | 5,275,541 |
| 2 | DuPage County | 932,877 |
| 3 | Lake County | 714,342 |
| 4 | Will County | 696,355 |
| 5 | Kane County | 516,522 |
| 6 | McHenry County | 310,229 |
| 7 | Winnebago County | 285,350 |
| 8 | Madison County | 265,859 |
| 9 | St. Clair County | 257,400 |
| 10 | Champaign County | 205,865 |
| 11 | Sangamon County | 196,343 |
| 12 | Peoria County | 181,830 |
| 13 | McLean County | 170,954 |
| 14 | Rock Island County | 144,672 |
| 15 | Kendall County | 131,869 |
| 16 | Tazewell County | 131,343 |
| 17 | La Salle County | 109,658 |
| 18 | Kankakee County | 107,502 |
| 19 | Macon County | 103,998 |
| 20 | DeKalb County | 100,420 |
| 21 | Vermilion County | 74,188 |
| 22 | Williamson County | 67,153 |
| 23 | Adams County | 65,737 |
| 24 | Whiteside County | 55,691 |
| 25 | Boone County | 53,448 |
| 26 | Jackson County | 52,974 |
| 27 | Grundy County | 52,533 |
| 28 | Ogle County | 51,788 |
| 29 | Knox County | 49,967 |
| 30 | Henry County | 49,284 |
| 31 | Coles County | 46,863 |
| 32 | Macoupin County | 44,967 |
| 33 | Stephenson County | 44,630 |
| 34 | Woodford County | 38,467 |
| 35 | Franklin County | 37,804 |
| 36 | Marion County | 37,729 |
| 37 | Jefferson County | 37,113 |
| 38 | Clinton County | 36,899 |
| 39 | Livingston County | 35,815 |
| 40 | Monroe County | 34,962 |
| 41 | Effingham County | 34,668 |
| 42 | Lee County | 34,145 |
| 43 | Christian County | 34,032 |
| 44 | Fulton County | 33,609 |
| 45 | Bureau County | 33,244 |
| 46 | Morgan County | 32,915 |
| 47 | Randolph County | 30,163 |
| 48 | Montgomery County | 28,288 |
| 49 | Logan County | 27,987 |
| 50 | McDonough County | 27,238 |
| 51 | Iroquois County | 27,077 |
| 52 | Saline County | 23,768 |
| 53 | Jo Daviess County | 22,035 |
| 54 | Jersey County | 21,512 |
| 55 | Fayette County | 21,488 |
| 56 | Shelby County | 20,990 |
| 57 | Perry County | 20,945 |
| 58 | Douglas County | 19,740 |
| 59 | Crawford County | 18,679 |
| 60 | Hancock County | 17,620 |
| 61 | Union County | 17,244 |
| 62 | Edgar County | 16,866 |
| 63 | Warren County | 16,835 |
| 64 | Bond County | 16,725 |
| 65 | Piatt County | 16,673 |
| 66 | Wayne County | 16,179 |
| 67 | Richland County | 15,813 |
| 68 | Carroll County | 15,702 |
| 69 | Mercer County | 15,699 |
| 70 | De Witt County | 15,516 |
| 71 | Clark County | 15,455 |
| 72 | Lawrence County | 15,280 |
| 73 | Pike County | 14,739 |
| 74 | Moultrie County | 14,526 |
| 75 | Massac County | 14,169 |
| 76 | White County | 13,877 |
| 77 | Washington County | 13,761 |
| 78 | Ford County | 13,534 |
| 79 | Johnson County | 13,308 |
| 80 | Clay County | 13,288 |
| 81 | Mason County | 13,086 |
| 82 | Cass County | 13,042 |
| 83 | Menard County | 12,297 |
| 84 | Greene County | 11,985 |
| 85 | Marshall County | 11,742 |
| 86 | Wabash County | 11,361 |
| 87 | Cumberland County | 10,450 |
| 88 | Jasper County | 9,287 |
| 89 | Hamilton County | 7,993 |
| 90 | Schuyler County | 6,902 |
| 91 | Henderson County | 6,387 |
| 92 | Edwards County | 6,245 |
| 93 | Brown County | 6,244 |
| 94 | Putnam County | 5,637 |
| 95 | Stark County | 5,400 |
| 96 | Alexander County | 5,240 |
| 97 | Pulaski County | 5,193 |
| 98 | Scott County | 4,949 |
| 99 | Gallatin County | 4,946 |
| 100 | Calhoun County | 4,437 |
| 101 | Pope County | 3,763 |
| 102 | Hardin County | 3,649 |
