Census ACS 2023 · 102 counties
Largest Counties in Illinois
Illinois has 102 counties with Census data available. The largest is Cook County with a population of 5,185,812. County-level data is important because counties are the primary unit of local government in most states, responsible for courts, elections, public health, and infrastructure. Population distribution across counties reveals where growth is concentrated and where rural decline may be occurring.
Source: Census ACS 2023 5-Year Estimates
| # | County | Population | Median Income |
|---|---|---|---|
| 1 | Woodford County | 38,348 | $85,629 |
| 2 | Winnebago County | 283,289 | $64,363 |
| 3 | Williamson County | 66,902 | $65,521 |
| 4 | Will County | 698,450 | $107,799 |
| 5 | Whiteside County | 55,192 | $64,536 |
| 6 | White County | 13,708 | $53,097 |
| 7 | Wayne County | 15,994 | $53,107 |
| 8 | Washington County | 13,682 | $75,652 |
| 9 | Warren County | 16,576 | $64,650 |
| 10 | Wabash County | 11,199 | $53,650 |
| 11 | Vermilion County | 73,179 | $54,537 |
| 12 | Union County | 16,972 | $56,420 |
| 13 | Tazewell County | 130,555 | $76,704 |
| 14 | Stephenson County | 44,042 | $61,943 |
| 15 | Stark County | 5,324 | $62,284 |
| 16 | St. Clair County | 254,777 | $70,178 |
| 17 | Shelby County | 20,867 | $68,457 |
| 18 | Scott County | 4,847 | $73,013 |
| 19 | Schuyler County | 6,826 | $66,059 |
| 20 | Sangamon County | 195,217 | $74,114 |
| 21 | Saline County | 23,387 | $54,945 |
| 22 | Rock Island County | 142,995 | $66,768 |
| 23 | Richland County | 15,675 | $60,404 |
| 24 | Randolph County | 30,142 | $68,870 |
| 25 | Putnam County | 5,600 | $77,526 |
| 26 | Pulaski County | 5,074 | $43,227 |
| 27 | Pope County | 3,757 | $62,500 |
| 28 | Pike County | 14,625 | $58,029 |
| 29 | Piatt County | 16,702 | $87,516 |
| 30 | Perry County | 20,810 | $59,286 |
| 31 | Peoria County | 179,831 | $64,938 |
| 32 | Ogle County | 51,536 | $79,244 |
| 33 | Moultrie County | 14,469 | $71,676 |
| 34 | Morgan County | 32,621 | $65,175 |
| 35 | Montgomery County | 28,078 | $61,863 |
| 36 | Monroe County | 34,969 | $101,635 |
| 37 | Mercer County | 15,619 | $71,710 |
| 38 | Menard County | 12,169 | $81,334 |
| 39 | McLean County | 170,882 | $78,329 |
| 40 | McHenry County | 311,366 | $102,836 |
| 41 | McDonough County | 27,102 | $50,434 |
| 42 | Massac County | 13,958 | $62,584 |
| 43 | Mason County | 12,878 | $62,127 |
| 44 | Marshall County | 11,715 | $69,818 |
| 45 | Marion County | 37,294 | $60,839 |
| 46 | Madison County | 264,631 | $74,800 |
| 47 | Macoupin County | 44,566 | $68,518 |
| 48 | Macon County | 102,591 | $62,449 |
| 49 | Logan County | 27,870 | $64,188 |
| 50 | Livingston County | 35,659 | $70,796 |
| 51 | Lee County | 34,058 | $68,459 |
| 52 | Lawrence County | 15,137 | $53,438 |
| 53 | LaSalle County | 109,049 | $72,281 |
| 54 | Lake County | 711,885 | $108,917 |
| 55 | Knox County | 49,294 | $53,291 |
| 56 | Kendall County | 135,053 | $110,474 |
| 57 | Kankakee County | 106,833 | $68,325 |
| 58 | Kane County | 516,097 | $100,678 |
| 59 | Johnson County | 13,350 | $65,203 |
| 60 | Jo Daviess County | 21,918 | $74,954 |
| 61 | Jersey County | 21,336 | $79,104 |
| 62 | Jefferson County | 36,808 | $61,102 |
| 63 | Jasper County | 9,233 | $71,094 |
| 64 | Jackson County | 52,706 | $45,572 |
| 65 | Iroquois County | 26,746 | $62,439 |
| 66 | Henry County | 48,948 | $69,912 |
| 67 | Henderson County | 6,284 | $65,651 |
| 68 | Hardin County | 3,623 | $57,155 |
| 69 | Hancock County | 17,434 | $65,044 |
| 70 | Hamilton County | 7,972 | $61,520 |
| 71 | Grundy County | 52,920 | $93,060 |
| 72 | Greene County | 11,837 | $60,976 |
| 73 | Gallatin County | 4,857 | $54,626 |
| 74 | Fulton County | 33,259 | $58,617 |
| 75 | Franklin County | 37,541 | $53,471 |
| 76 | Ford County | 13,396 | $60,782 |
| 77 | Fayette County | 21,380 | $57,113 |
| 78 | Effingham County | 34,505 | $75,380 |
| 79 | Edwards County | 6,118 | $59,386 |
| 80 | Edgar County | 16,637 | $56,909 |
| 81 | DuPage County | 927,263 | $110,502 |
| 82 | Douglas County | 19,686 | $74,186 |
| 83 | DeKalb County | 100,512 | $69,022 |
| 84 | De Witt County | 15,461 | $64,802 |
| 85 | Cumberland County | 10,378 | $69,826 |
| 86 | Crawford County | 18,588 | $67,614 |
| 87 | Cook County | 5,185,812 | $81,797 |
| 88 | Coles County | 46,689 | $56,040 |
| 89 | Clinton County | 36,899 | $82,314 |
| 90 | Clay County | 13,173 | $57,266 |
| 91 | Clark County | 15,328 | $70,625 |
| 92 | Christian County | 33,684 | $59,253 |
| 93 | Champaign County | 206,098 | $63,091 |
| 94 | Cass County | 12,826 | $64,907 |
| 95 | Carroll County | 15,621 | $60,871 |
| 96 | Calhoun County | 4,406 | $92,095 |
| 97 | Bureau County | 33,027 | $65,894 |
| 98 | Brown County | 6,320 | $72,288 |
| 99 | Boone County | 53,316 | $81,638 |
| 100 | Bond County | 16,627 | $61,603 |
| 101 | Alexander County | 5,042 | $43,523 |
| 102 | Adams County | 65,166 | $64,962 |
More Rankings for Illinois
Frequently Asked Questions
Cook County is the #1 ranked county in Illinois by population, with a value of 5,185,812 according to Census ACS 2023 data.
Illinois has 102 counties tracked in Census ACS 2023 data.
All data comes from the American Community Survey (ACS) 2023 5-Year estimates by the US Census Bureau.
Data from the American Community Survey 2023 5-Year estimates. Covers all counties in Illinois.