How many counties in Illinois? All 102 listed
Quick answer
Illinois has 102 counties and county equivalents holding 12,692,653 residents. The most populous county in Illinois is Cook County with 5,185,812 residents; the smallest is Hardin County. County boundaries divide the state's land area — measured in square miles by the Census Bureau — into the units used for property assessment, elections and local sales tax. The statewide sales tax base rate is 6.25%, before county and city add-ons.
All 102 counties
Ranked by population, Census 2019-2023 ACS 5-year estimates.
| County | Population | Median income | Median home value | Median rent |
|---|---|---|---|---|
| Cook County | 5,185,812 | $81,797 | $305,200 | $1,381 |
| DuPage County | 927,263 | $110,502 | $374,100 | $1,628 |
| Lake County | 711,885 | $108,917 | $326,600 | $1,434 |
| Will County | 698,450 | $107,799 | $298,000 | $1,413 |
| Kane County | 516,097 | $100,678 | $303,000 | $1,404 |
| McHenry County | 311,366 | $102,836 | $286,900 | $1,358 |
| Winnebago County | 283,289 | $64,363 | $155,100 | $986 |
| Madison County | 264,631 | $74,800 | $167,900 | $969 |
| St. Clair County | 254,777 | $70,178 | $168,800 | $1,032 |
| Champaign County | 206,098 | $63,091 | $205,100 | $1,018 |
| Sangamon County | 195,217 | $74,114 | $170,300 | $954 |
| Peoria County | 179,831 | $64,938 | $152,600 | $946 |
| McLean County | 170,882 | $78,329 | $198,300 | $992 |
| Rock Island County | 142,995 | $66,768 | $144,700 | $863 |
| Kendall County | 135,053 | $110,474 | $298,900 | $1,763 |
| Tazewell County | 130,555 | $76,704 | $164,500 | $898 |
| LaSalle County | 109,049 | $72,281 | $154,900 | $906 |
| Kankakee County | 106,833 | $68,325 | $185,700 | $1,075 |
| Macon County | 102,591 | $62,449 | $121,800 | $797 |
| DeKalb County | 100,512 | $69,022 | $231,900 | $1,041 |
| Vermilion County | 73,179 | $54,537 | $92,900 | $802 |
| Williamson County | 66,902 | $65,521 | $145,600 | $897 |
| Adams County | 65,166 | $64,962 | $155,900 | $826 |
| Whiteside County | 55,192 | $64,536 | $125,800 | $808 |
| Boone County | 53,316 | $81,638 | $198,600 | $1,011 |
| Grundy County | 52,920 | $93,060 | $259,200 | $1,137 |
| Jackson County | 52,706 | $45,572 | $125,000 | $746 |
| Ogle County | 51,536 | $79,244 | $184,100 | $901 |
| Knox County | 49,294 | $53,291 | $104,900 | $725 |
| Henry County | 48,948 | $69,912 | $145,300 | $837 |
| Coles County | 46,689 | $56,040 | $121,900 | $793 |
| Macoupin County | 44,566 | $68,518 | $126,100 | $789 |
| Stephenson County | 44,042 | $61,943 | $127,500 | $764 |
| Woodford County | 38,348 | $85,629 | $193,800 | $907 |
| Franklin County | 37,541 | $53,471 | $87,700 | $771 |
| Marion County | 37,294 | $60,839 | $100,100 | $771 |
| Clinton County | 36,899 | $82,314 | $180,500 | $934 |
| Jefferson County | 36,808 | $61,102 | $118,400 | $862 |
| Livingston County | 35,659 | $70,796 | $131,500 | $855 |
| Monroe County | 34,969 | $101,635 | $265,600 | $996 |
| Effingham County | 34,505 | $75,380 | $179,800 | $734 |
| Lee County | 34,058 | $68,459 | $155,100 | $853 |
| Christian County | 33,684 | $59,253 | $112,100 | $729 |
| Fulton County | 33,259 | $58,617 | $102,500 | $808 |
| Bureau County | 33,027 | $65,894 | $121,900 | $838 |
| Morgan County | 32,621 | $65,175 | $128,700 | $710 |
| Randolph County | 30,142 | $68,870 | $134,100 | $760 |
| Montgomery County | 28,078 | $61,863 | $102,200 | $715 |
| Logan County | 27,870 | $64,188 | $125,900 | $804 |
| McDonough County | 27,102 | $50,434 | $103,500 | $730 |
| Iroquois County | 26,746 | $62,439 | $125,400 | $793 |
| Saline County | 23,387 | $54,945 | $92,900 | $711 |
| Jo Daviess County | 21,918 | $74,954 | $193,900 | $795 |
| Fayette County | 21,380 | $57,113 | $114,700 | $740 |
| Jersey County | 21,336 | $79,104 | $168,800 | $794 |
| Shelby County | 20,867 | $68,457 | $130,400 | $762 |
| Perry County | 20,810 | $59,286 | $105,200 | $714 |
| Douglas County | 19,686 | $74,186 | $142,600 | $818 |
| Crawford County | 18,588 | $67,614 | $113,700 | $761 |
| Hancock County | 17,434 | $65,044 | $108,400 | $755 |
| Union County | 16,972 | $56,420 | $131,700 | $658 |
| Piatt County | 16,702 | $87,516 | $173,200 | $950 |
| Edgar County | 16,637 | $56,909 | $95,700 | $757 |
| Bond County | 16,627 | $61,603 | $133,100 | $735 |
| Warren County | 16,576 | $64,650 | $101,300 | $694 |
| Wayne County | 15,994 | $53,107 | $109,400 | $632 |
| Richland County | 15,675 | $60,404 | $106,600 | $754 |
| Carroll County | 15,621 | $60,871 | $113,500 | $784 |
| Mercer County | 15,619 | $71,710 | $139,300 | $757 |
| De Witt County | 15,461 | $64,802 | $124,200 | $857 |
| Clark County | 15,328 | $70,625 | $123,100 | $828 |
| Lawrence County | 15,137 | $53,438 | $95,500 | $810 |
| Pike County | 14,625 | $58,029 | $100,100 | $659 |
| Moultrie County | 14,469 | $71,676 | $121,500 | $773 |
| Massac County | 13,958 | $62,584 | $118,000 | $793 |
| White County | 13,708 | $53,097 | $100,100 | $706 |
| Washington County | 13,682 | $75,652 | $149,800 | $776 |
| Ford County | 13,396 | $60,782 | $118,100 | $836 |
| Johnson County | 13,350 | $65,203 | $148,200 | $634 |
| Clay County | 13,173 | $57,266 | $94,300 | $709 |
| Mason County | 12,878 | $62,127 | $106,100 | $760 |
| Cass County | 12,826 | $64,907 | $95,500 | $723 |
| Menard County | 12,169 | $81,334 | $179,300 | $780 |
| Greene County | 11,837 | $60,976 | $94,400 | $800 |
| Marshall County | 11,715 | $69,818 | $137,800 | $767 |
| Wabash County | 11,199 | $53,650 | $103,900 | $774 |
| Cumberland County | 10,378 | $69,826 | $117,700 | $756 |
| Jasper County | 9,233 | $71,094 | $122,900 | $766 |
| Hamilton County | 7,972 | $61,520 | $108,800 | $566 |
| Schuyler County | 6,826 | $66,059 | $106,200 | $836 |
| Brown County | 6,320 | $72,288 | $142,200 | $724 |
| Henderson County | 6,284 | $65,651 | $101,600 | $834 |
| Edwards County | 6,118 | $59,386 | $97,500 | $746 |
| Putnam County | 5,600 | $77,526 | $167,800 | $804 |
| Stark County | 5,324 | $62,284 | $103,500 | $765 |
| Pulaski County | 5,074 | $43,227 | $81,000 | $625 |
| Alexander County | 5,042 | $43,523 | $58,700 | $540 |
| Gallatin County | 4,857 | $54,626 | $84,700 | $500 |
| Scott County | 4,847 | $73,013 | $101,700 | $669 |
| Calhoun County | 4,406 | $92,095 | $174,000 | $479 |
| Pope County | 3,757 | $62,500 | $165,300 | $438 |
| Hardin County | 3,623 | $57,155 | $91,700 | $342 |
Source: US Census Bureau, ACS 2019-2023 5-year estimates · rates as published for 2019-2023 ACS 5-year
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