Population of Counties in Illinois (2018)

Name 2018 Population Growth Since 2010
Cook County5,211,2630.23%
DuPage County930,1281.31%
Lake County703,520-0.11%
Will County692,6612.04%
Kane County534,6673.59%
McHenry County309,1220.02%
Winnebago County284,778-3.49%
Madison County265,428-1.45%
St. Clair County262,479-2.91%
Champaign County209,3993.90%
Sangamon County196,452-0.66%
Peoria County183,011-1.72%
McLean County172,2901.46%
Rock Island County144,808-1.90%
Tazewell County133,526-1.45%
Kendall County126,2189.40%
LaSalle County110,067-3.29%
Kankakee County109,605-3.36%
Macon County105,801-4.49%
DeKalb County104,733-0.39%
Vermilion County77,909-4.57%
Williamson County67,3281.35%
Adams County66,234-1.39%
Jackson County58,284-3.48%
Whiteside County56,118-4.04%
Boone County53,513-1.10%
Coles County51,979-3.50%
Ogle County51,063-4.42%
Knox County50,638-4.29%
Grundy County50,5860.87%
Henry County49,328-2.23%
Macoupin County45,446-4.92%
Stephenson County45,054-5.36%
Franklin County39,041-2.46%
Woodford County38,7260.14%
Jefferson County38,179-1.49%
Marion County37,902-3.85%
Clinton County37,614-0.60%
Livingston County36,518-6.02%
Fulton County35,110-5.30%
Lee County34,406-4.36%
Effingham County34,132-0.25%
Monroe County34,0973.31%
Morgan County33,798-4.82%
Bureau County33,243-4.90%
Christian County33,102-4.80%
Randolph County32,423-3.10%
McDonough County30,823-5.54%
Logan County29,245-3.42%
Montgomery County28,790-4.33%
Iroquois County27,876-6.14%
Saline County24,102-3.21%
Jersey County21,941-4.48%
Fayette County21,784-1.56%
Shelby County21,719-2.88%
Jo Daviess County21,594-4.64%
Perry County21,285-4.63%
Douglas County19,748-1.20%
Crawford County18,961-4.24%
Hancock County18,020-5.61%
Edgar County17,328-6.37%
Warren County17,167-3.12%
Union County17,000-4.13%
Bond County16,948-4.72%
Wayne County16,495-1.45%
Piatt County16,445-1.59%
Lawrence County16,168-4.56%
De Witt County15,942-3.92%
Richland County15,901-1.81%
Pike County15,821-3.50%
Clark County15,767-3.22%
Mercer County15,618-4.83%
Moultrie County14,688-1.12%
Carroll County14,518-5.66%
Massac County14,344-6.72%
Washington County14,030-4.64%
White County13,938-4.53%
Mason County13,715-6.39%
Ford County13,280-5.69%
Clay County13,269-4.03%
Greene County13,174-5.15%
Johnson County12,9002.31%
Cass County12,505-8.29%
Menard County12,245-3.55%
Marshall County11,730-7.13%
Wabash County11,489-3.58%
Cumberland County10,908-1.34%
Jasper County9,578-1.48%
Hamilton County8,194-2.98%
Schuyler County7,035-6.64%
Henderson County6,795-7.46%
Brown County6,716-2.93%
Edwards County6,486-3.68%
Alexander County6,315-23.04%
Putnam County5,727-4.74%
Pulaski County5,509-10.07%
Stark County5,434-9.01%
Gallatin County5,080-8.86%
Scott County5,002-6.10%
Calhoun County4,833-5.16%
Pope County4,325-3.24%
Hardin County4,046-6.23%