Illinois Counties by Population (2024)

Population

500K

1M

1.5M

2M

2.5M

3M

3.5M

4M

4.5M

5M

Hover/click a county for data.

102 counties

County
2024 Pop.
Change (2020)
Area (mi²)
Density (/mi²)
Location
Cook County5,062,578-3.82%3655,357Cook County location
DuPage County920,762-1.13%1272,807DuPage County location
Lake County707,621-0.79%1711,594Lake County location
Will County703,4100.94%323841Will County location
Kane County515,825-0.07%200994Kane County location
McHenry County314,0421.34%233521McHenry County location
Winnebago County280,302-1.62%198546Winnebago County location
Madison County261,932-1.4%276366Madison County location
St. Clair County249,771-2.75%254380St. Clair County location
Champaign County205,119-0.26%384206Champaign County location
Sangamon County192,831-1.69%335222Sangamon County location
Peoria County177,026-2.37%239286Peoria County location
McLean County169,964-0.58%457144McLean County location
Kendall County142,4587.63%124445Kendall County location
Rock Island County140,913-2.39%165330Rock Island County location
Tazewell County129,472-1.23%249200Tazewell County location
LaSalle County108,437-0.89%43896LaSalle County location
Kankakee County105,882-1.29%261157Kankakee County location
DeKalb County100,3530.08%244159DeKalb County location
Macon County99,849-3.76%224172Macon County location
Vermilion County71,201-3.79%34779Vermilion County location
Williamson County66,868-0.37%162159Williamson County location
Adams County64,326-1.96%33075Adams County location
Whiteside County54,441-2.02%26480Whiteside County location
Grundy County54,0072.84%161129Grundy County location
Boone County53,336-0.01%108190Boone County location
Jackson County51,805-2.05%22589Jackson County location
Ogle County51,185-0.98%29367Ogle County location
Henry County48,300-1.76%31859Henry County location
Knox County48,202-3.19%27667Knox County location
Coles County45,774-2.11%19690Coles County location
Macoupin County43,913-2.1%33351Macoupin County location
Stephenson County42,654-4.15%21876Stephenson County location
Woodford County38,393-0.05%20473Woodford County location
Franklin County37,061-1.69%15891Franklin County location
Clinton County36,633-0.73%18377Clinton County location
Marion County36,441-3.22%22164Marion County location
Jefferson County36,221-2.09%22063Jefferson County location
Livingston County35,123-1.87%40334Livingston County location
Monroe County34,913-0.11%14991Monroe County location
Effingham County34,362-0.98%18572Effingham County location
Lee County33,370-2.03%28046Lee County location
Christian County33,066-2.63%27447Christian County location
Bureau County32,631-1.69%33538Bureau County location
Fulton County32,147-4%33437Fulton County location
Morgan County31,982-2.63%22056Morgan County location
Randolph County29,604-1.62%22251Randolph County location
Logan County27,514-1.43%23945Logan County location
Montgomery County27,425-2.76%27239Montgomery County location
McDonough County26,764-1.24%22745McDonough County location
Iroquois County25,779-4.47%43123Iroquois County location
Saline County22,694-4.2%14760Saline County location
Jo Daviess County21,667-1.77%23236Jo Daviess County location
Fayette County21,058-2.01%27629Fayette County location
Jersey County20,991-2.34%14357Jersey County location
Perry County20,494-1.88%17146Perry County location
Shelby County20,426-2.36%29327Shelby County location
Douglas County19,591-0.88%16147Douglas County location
Crawford County18,105-2.93%17141Crawford County location
Hancock County17,118-2.42%30622Hancock County location
Piatt County16,7530.43%16938Piatt County location
Union County16,562-3.62%15940Union County location
Bond County16,364-1.92%14743Bond County location
Edgar County16,283-3%24026Edgar County location
Warren County16,010-4.82%20930Warren County location
Wayne County15,679-2.77%27622Wayne County location
Carroll County15,473-1.27%17235Carroll County location
Mercer County15,441-1.22%21728Mercer County location
Richland County15,421-2.34%13943Richland County location
De Witt County15,365-0.62%15439De Witt County location
Clark County15,016-2.68%19330Clark County location
Lawrence County14,735-3.49%14440Lawrence County location
Moultrie County14,309-1.19%13043Moultrie County location
Pike County14,185-3.11%32117Pike County location
Massac County13,495-4.51%9157Massac County location
Washington County13,449-2%21724Washington County location
Johnson County13,261-0.43%13339Johnson County location
Ford County13,244-1.99%18827Ford County location
White County13,207-4.35%19127White County location
Clay County12,921-2.65%18128Clay County location
Cass County12,554-3.36%14533Cass County location
Mason County12,347-5.44%20823Mason County location
Menard County11,836-3.54%12138Menard County location
Marshall County11,695-0.19%14930Marshall County location
Greene County11,446-4.11%21021Greene County location
Wabash County10,844-4.19%8649Wabash County location
Cumberland County10,214-2.1%13430Cumberland County location
Jasper County9,116-1.35%19118Jasper County location
Hamilton County7,841-1.98%16818Hamilton County location
Schuyler County6,713-2.26%16915Schuyler County location
Brown County6,2720.72%11820Brown County location
Henderson County6,008-5.16%14616Henderson County location
Edwards County5,878-5.32%8626Edwards County location
Putnam County5,569-1.08%6235Putnam County location
Stark County5,123-4.81%11118Stark County location
Pulaski County4,872-5.58%7724Pulaski County location
Scott County4,649-5.91%9719Scott County location
Alexander County4,549-11.99%9119Alexander County location
Gallatin County4,517-8.47%12514Gallatin County location
Calhoun County4,281-2.86%9817Calhoun County location
Pope County3,668-2.29%14210Pope County location
Hardin County3,566-2.09%6820Hardin County location
  1. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  3. American Community Survey (2009 - 2013)
  4. Census QuickFacts
  5. Historical Populations of States and Counties (1790 - 1990)

Sources