Illinois Illinois State Facts

There are fewer men than woman in Illinois. The overall gender ratio is 96 men to 100 women.

The Illinois flag was adopted on June 27, 1969. The flag has been ranked the 34th best U.S. flag by a leading Vexillology Organization.

The Illinois quarter was the 21st quarter released overall. The quarter was released on January 2, 2003.

Recent estimates put Illinois's population at around 12,881,000 people (5th out of 56).The population density is 232.0 people per square mile (18th out of 56).

Someone from Illinois is known as a Illinoisan. View our List of Adjectival and Demonyms for all the States.

Illinois was the 21st state when it joined the United States on December 3, 1818. Prior to 1818, Illinois was known as "Illinois Territory."

Essential Illinois Facts

  • IL
    Postal Code
    The Illinois postal code is IL. This abbreviation has been used since the USPS first established official codes in October 1963.
  • Gender Ratio
    Gender Ratio: 96 Men to 100 Women
    Male Population: 6,320,886 men
    Female Population: 6,559,694 women
  • State Flag
    The 7 main colors in the Illinois flag are #FFFFFF, #785A3C, #BE0A2F, #FFE60F, #B4B4B4, #000000, and #002768
  • State Quarter
    The Illinois Quarter was released in January 01, 2003.
    Total Mintage: 0.46 billion.
    Engraver: Donna Weaver
  • Population and Area
    Population: 12,880,580 people
    Land Area: 55,519 square miles
    Population Density: 12,880,580 people per square mile

Areas Codes in Illinois (15)

  • 217
  • 224
  • 309
  • 312
  • 314
  • 331
  • 563
  • 608
  • 618
  • 630
  • 708
  • 773
  • 779
  • 815
  • 847

Illinois Counties (102)

County Top Cities
Adams County Camp Point, Clayton, Coatsburg, Fowler, Golden, and La Prairie
Alexander County Cairo, Mc Clure, Miller City, Olive Branch, Tamms, and Thebes
Bond County Donnellson, Greenville, Keyesport, Pierron, Pocahontas, and Smithboro
Boone County Belvidere, Caledonia, Capron, Garden Prairie, and Poplar Grove
Brown County Mount Sterling, Timewell, and Versailles
Bureau County Arlington, Bradford, Buda, Bureau, Cherry, and Dalzell
Calhoun County Batchtown, Brussels, Golden Eagle, Hamburg, Hardin, and Kampsville
Carroll County Chadwick, Lanark, Milledgeville, Mount Carroll, Savanna, and Shannon
Cass County Arenzville, Ashland, Beardstown, Bluff Springs, Chandlerville, and Virginia
Champaign County Bondville, Broadlands, Champaign, Dewey, Fisher, and Foosland
Christian County Assumption, Bulpitt, Edinburg, Harvel, Kincaid, and Morrisonville
Clark County Casey, Dennison, Marshall, Martinsville, West Union, and West York
Clay County Clay City, Edgewood, Flora, Ingraham, Louisville, and Sailor Springs
Clinton County Albers, Aviston, Bartelso, Beckemeyer, Breese, and Carlyle
Coles County Ashmore, Charleston, Humboldt, Janesville, Lerna, and Mattoon
Cook County Alsip, Arlington Heights, Barrington, Bedford Park, Bellwood, and Berkeley
Crawford County Annapolis, Flat Rock, Hutsonville, Oblong, Palestine, and Robinson
Cumberland County Greenup, Jewett, Neoga, Sigel, Toledo, and Trilla
DeKalb County Clare, Cortland, Dekalb, Genoa, Hinckley, and Kingston
De Witt County Clinton, Dewitt, Farmer City, Kenney, Lane, and Wapella
Douglas County Arcola, Arthur, Atwood, Camargo, Hindsboro, and Murdock
DuPage County Addison, Aurora, Bartlett, Bensenville, Bloomingdale, and Carol Stream
Edgar County Brocton, Chrisman, Hume, Kansas, Metcalf, and Paris
Edwards County Albion, Bone Gap, Browns, Grayville, and West Salem
Effingham County Altamont, Beecher City, Dieterich, Effingham, Mason, and Shumway
Fayette County Bingham, Brownstown, Farina, Hagarstown, Mulberry Grove, and Ramsey
Ford County Cabery, Elliott, Gibson City, Kempton, Melvin, and Paxton
Franklin County Benton, Buckner, Christopher, Coello, Ewing, and Frankfort Heights
Fulton County Astoria, Bryant, Canton, Cuba, Dunfermline, and Ellisville
Gallatin County Equality, Junction, New Haven, Omaha, Ridgway, and Shawneetown
Greene County Carrollton, Eldred, Greenfield, Hillview, Kane, and Patterson
Grundy County Braceville, Coal City, Gardner, Kinsman, Mazon, and Minooka
Hamilton County Broughton, Dahlgren, Dale, Macedonia, Mc Leansboro, and Springerton
Hancock County Augusta, Basco, Bowen, Carthage, Colusa, and Dallas City
Hardin County Cave In Rock, Elizabethtown, Karbers Ridge, and Rosiclare
Henderson County Biggsville, Carman, Gladstone, Lomax, Media, and Oquawka
Henry County Alpha, Andover, Annawan, Atkinson, Bishop Hill, and Cambridge
Iroquois County Ashkum, Beaverville, Buckley, Cissna Park, Claytonville, and Clifton
Jackson County Ava, Campbell Hill, Carbondale, De Soto, Dowell, and Elkville
Jasper County Hidalgo, Montrose, Newton, Sainte Marie, West Liberty, and Wheeler
Jefferson County Belle Rive, Bluford, Bonnie, Dix, Ina, and Mount Vernon
Jersey County Brighton, Dow, Elsah, Fidelity, Fieldon, and Grafton
Jo Daviess County Apple River, East Dubuque, Elizabeth, Galena, Hanover, and Nora
Johnson County Boles, Buncombe, Cypress, Goreville, Grantsburg, and New Burnside
Kane County Aurora, Batavia, Big Rock, Burlington, Carpentersville, and Dundee
Kankakee County Aroma Park, Bonfield, Bourbonnais, Bradley, Buckingham, and Chebanse
Kendall County Bristol, Millbrook, Montgomery, Newark, Oswego, and Plano
Knox County Abingdon, Altona, Dahinda, East Galesburg, Galesburg, and Gilson
Lake County Antioch, Buffalo Grove, Deerfield, Fort Sheridan, Fox Lake, and Grayslake
LaSalle County Cedar Point, Dana, Earlville, Grand Ridge, La Salle, and Leland
Lawrence County Bridgeport, Lawrenceville, Saint Francisville, and Sumner
Lee County Amboy, Ashton, Compton, Dixon, Eldena, and Franklin Grove
Livingston County Ancona, Blackstone, Campus, Chatsworth, Cornell, and Cullom
Logan County Atlanta, Beason, Chestnut, Cornland, Elkhart, and Emden
Macon County Argenta, Blue Mound, Boody, Decatur, Elwin, and Forsyth
Macoupin County Benld, Bunker Hill, Carlinville, Chesterfield, Eagarville, and Gillespie
Madison County Alhambra, Alton, Bethalto, Collinsville, Cottage Hills, and Dorsey
Marion County Alma, Centralia, Iuka, Kell, Kinmundy, and Odin
Marshall County Camp Grove, Henry, La Rose, Lacon, Sparland, and Toluca
Mason County Bath, Easton, Forest City, Havana, Kilbourne, and Manito
Massac County Belknap, Brookport, and Metropolis
McDonough County Adair, Bardolph, Blandinsville, Bushnell, Colchester, and Good Hope
McHenry County Alden, Algonquin, Cary, Crystal Lake, Fox River Grove, and Harvard
McLean County Anchor, Arrowsmith, Bellflower, Bloomington, Carlock, and Chenoa
Menard County Athens, Greenview, Lincolns New Salem, Oakford, Petersburg, and Tallula
Mercer County Aledo, Joy, Keithsburg, Matherville, New Boston, and New Windsor
Monroe County Columbia, Fults, Hecker, Maeystown, Renault, and Valmeyer
Montgomery County Butler, Coffeen, Farmersville, Fillmore, Hillsboro, and Irving
Morgan County Alexander, Chapin, Concord, Franklin, Jacksonville, and Literberry
Moultrie County Bethany, Dalton City, Gays, Lovington, and Sullivan
Ogle County Baileyville, Byron, Chana, Creston, Davis Junction, and Esmond
Peoria County Brimfield, Chillicothe, Dunlap, East Peoria, Edelstein, and Edwards
Perry County Coulterville, Cutler, Du Quoin, Pinckneyville, Tamaroa, and Willisville
Piatt County Bement, Cerro Gordo, Cisco, De Land, Hammond, and La Place
Pike County Barry, Baylis, Chambersburg, Griggsville, Hull, and Kinderhook
Pope County Eddyville, Golconda, and Herod
Pulaski County Grand Chain, Joppa, Karnak, Mound City, Mounds, and Olmsted
Putnam County Granville, Hennepin, Magnolia, Mark, Mc Nabb, and Putnam
Randolph County Baldwin, Chester, Ellis Grove, Evansville, Menard, and Modoc
Richland County Calhoun, Claremont, Dundas, Noble, Olney, and Parkersburg
Rock Island County Andalusia, Barstow, Buffalo Prairie, Carbon Cliff, Coal Valley, and Cordova
Saline County Carrier Mills, Eldorado, Galatia, Harrisburg, Muddy, and Raleigh
Sangamon County Auburn, Buffalo, Cantrall, Chatham, Dawson, and Divernon
Schuyler County Browning, Camden, Frederick, Huntsville, Littleton, and Rushville
Scott County Alsey, Bluffs, Manchester, and Winchester
Shelby County Cowden, Findlay, Herrick, Lakewood, Mode, and Moweaqua
Stark County Castleton, La Fayette, Speer, Toulon, and Wyoming
St. Clair County Belleville, Caseyville, Dupo, East Carondelet, East Saint Louis, and Fairview Heights
Stephenson County Cedarville, Dakota, Davis, Eleroy, Freeport, and German Valley
Tazewell County Armington, Creve Coeur, Delavan, East Peoria, Green Valley, and Groveland
Union County Alto Pass, Anna, Cobden, Dongola, Jonesboro, and Millcreek
Vermilion County Allerton, Alvin, Armstrong, Bismarck, Catlin, and Collison
Wabash County Allendale, Bellmont, Keensburg, Lancaster, and Mount Carmel
Warren County Alexis, Avon, Berwick, Cameron, Gerlaw, and Kirkwood
Washington County Addieville, Ashley, Du Bois, Hoyleton, Irvington, and Nashville
Wayne County Barnhill, Cisne, Ellery, Fairfield, Geff, and Golden Gate
White County Burnt Prairie, Carmi, Crossville, Emma, Enfield, and Maunie
Whiteside County Albany, Deer Grove, Erie, Fenton, Fulton, and Galt
Williamson County Cambria, Carbondale, Carterville, Colp, Creal Springs, and Energy
Will County Aurora, Beecher, Bolingbrook, Braidwood, Channahon, and Crest Hill
Winnebago County Cherry Valley, Durand, Loves Park, Machesney Park, Pecatonica, and Rockford
Woodford County Benson, Congerville, Deer Creek, El Paso, Eureka, and Goodfield
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