Maps of Illinois are an invaluable area of ancestral and family history research, notably if you live far from where your ancestor was living.
Given that the political borders of Illinois have changed frequently over the years, historic maps are important in helping you to uncover the exact location of your ancestor’s hometown, what land they owned, just who his or her neighbors happen to be, and a lot more besides.
Maps of Illinois are an excellent resource for getting started with your research because they give relevant and accurate information instantly and present it in a clear and easily understandable format.
The 10 largest cities in Illinois are Chicago, Aurora, Rockford, Joliet, Naperville, Springfield, Peoria, Elgin, Waukegan, and Cicero.
Learn more historical facts about Illinois counties here.
Interactive Map of Illinois County Formation History
AniMap Plus 3.0, with the permission of the Goldbug Company
List of Every Illinois County
Adams County
Established in 1825, Adams County has a population of approximately 66,000 residents. The county seat is Quincy, and it is located in the western part of the state.
Alexander County
Established in 1819, Alexander County has a population of around 6,700 residents. The county seat is Cairo, and it is located in the southernmost part of Illinois, bordered by the Mississippi River and the Ohio River.
Bond County
Established in 1817, Bond County has a population of about 17,000 residents. The county seat is Greenville, and it is located in central Illinois.
Boone County
Established in 1837, Boone County has a population of approximately 55,000 residents. The county seat is Belvidere, and it is located in the northern part of the state.
Brown County
Established in 1839, Brown County has a population of around 6,500 residents. The county seat is Mount Sterling, and it is located in western Illinois.
Bureau County
Established in 1837, Bureau County has a population of about 32,000 residents. The county seat is Princeton, and it is located in north-central Illinois.
Calhoun County
Established in 1825, Calhoun County has a population of approximately 4,700 residents. The county seat is Hardin, and it is located in western Illinois, bordered by the Illinois River.
Carroll County
Established in 1839, Carroll County has a population of around 14,000 residents. The county seat is Mount Carroll, and it is located in northwestern Illinois.
Cass County
Established in 1837, Cass County has a population of about 12,000 residents. The county seat is Virginia, and it is located in central Illinois.
Champaign County
Established in 1833, Champaign County has a population of approximately 209,000 residents. The county seat is Urbana, and it is located in east-central Illinois, home to the University of Illinois.
Christian County
Established in 1839, Christian County has a population of around 32,000 residents. The county seat is Taylorville, and it is located in central Illinois.
Clark County
Established in 1819, Clark County has a population of approximately 15,000 residents. The county seat is Marshall, and it is located in eastern Illinois.
Clay County
Established in 1824, Clay County has a population of about 13,000 residents. The county seat is Louisville, and it is located in southeastern Illinois.
Clinton County
Established in 1824, Clinton County has a population of around 39,000 residents. The county seat is Carlyle, and it is located in southern Illinois.
Coles County
Established in 1830, Coles County has a population of approximately 51,000 residents. The county seat is Charleston, and it is located in east-central Illinois.
Cook County
Established in 1831, Cook County is the most populous county in Illinois, with over 5 million residents. The county seat is Chicago, and it is located in northeastern Illinois.
Crawford County
Established in 1816, Crawford County has a population of around 18,000 residents. The county seat is Robinson, and it is located in southeastern Illinois.
Cumberland County
Established in 1843, Cumberland County has a population of approximately 10,000 residents. The county seat is Toledo, and it is located in east-central Illinois.
DeKalb County
Established in 1837, DeKalb County has a population of around 105,000 residents. The county seat is Sycamore, and it is located in northern Illinois.
DeWitt County
Established in 1839, DeWitt County has a population of about 15,000 residents. The county seat is Clinton, and it is located in central Illinois.
Douglas County
Established in 1859, Douglas County has a population of around 19,000 residents. The county seat is Tuscola, and it is located in east-central Illinois.
DuPage County
Established in 1839, DuPage County has a population of approximately 929,000 residents. The county seat is Wheaton, and it is located in northeastern Illinois.
Edgar County
Established in 1823, Edgar County has a population of around 17,000 residents. The county seat is Paris, and it is located in east-central Illinois.
Edwards County
Established in 1814, Edwards County has a population of about 6,500 residents. The county seat is Albion, and it is located in southeastern Illinois.
Effingham County
Established in 1831, Effingham County has a population of approximately 34,000 residents. The county seat is Effingham, and it is located in east-central Illinois.
Fayette County
Established in 1821, Fayette County has a population of around 21,000 residents. The county seat is Vandalia, and it is located in southern Illinois.
Ford County
Established in 1859, Ford County has a population of about 13,000 residents. The county seat is Paxton, and it is located in east-central Illinois.
Franklin County
Established in 1818, Franklin County has a population of approximately 38,000 residents. The county seat is Benton, and it is located in southern Illinois.
Fulton County
Established in 1823, Fulton County has a population of around 34,000 residents. The county seat is Lewistown, and it is located in western Illinois.
Gallatin County
Established in 1812, Gallatin County has a population of about 5,600 residents. The county seat is Shawneetown, and it is located in southern Illinois.
Greene County
Established in 1821, Greene County has a population of around 12,000 residents. The county seat is Carrollton, and it is located in southwestern Illinois.
Grundy County
Established in 1841, Grundy County has a population of approximately 51,000 residents. The county seat is Morris, and it is located in northeastern Illinois.
Hamilton County
Established in 1821, Hamilton County has a population of about 8,000 residents. The county seat is McLeansboro, and it is located in southern Illinois.
Hancock County
Established in 1829, Hancock County has a population of around 17,000 residents. The county seat is Carthage, and it is located in western Illinois.
Hardin County
Established in 1839, Hardin County has a population of approximately 3,900 residents. The county seat is Elizabethtown, and it is located in southern Illinois.
Henderson County
Established in 1841, Henderson County has a population of about 6,700 residents. The county seat is Oquawka, and it is located in western Illinois.
Henry County
Established in 1825, Henry County has a population of around 48,000 residents. The county seat is Cambridge, and it is located in northwestern Illinois.
Iroquois County
Established in 1833, Iroquois County has a population of approximately 28,000 residents. The county seat is Watseka, and it is located in east-central Illinois.
Jackson County
Established in 1816, Jackson County has a population of around 57,000 residents. The county seat is Murphysboro, and it is located in southern Illinois.
Jasper County
Established in 1831, Jasper County has a population of about 9,500 residents. The county seat is Newton, and it is located in southeastern Illinois.
Jefferson County
Established in 1819, Jefferson County has a population of approximately 38,000 residents. The county seat is Mount Vernon, and it is located in southern Illinois.
Jersey County
Established in 1839, Jersey County has a population of around 22,000 residents. The county seat is Jerseyville, and it is located in southwestern Illinois.
Jo Daviess County
Established in 1827, Jo Daviess County has a population of about 22,000 residents. The county seat is Galena, and it is located in northwestern Illinois.
Johnson County
Established in 1812, Johnson County has a population of approximately 12,000 residents. The county seat is Vienna, and it is located in southern Illinois.
Kane County
Established in 1836, Kane County has a population of around 532,000 residents. The county seat is Geneva, and it is located in northeastern Illinois.
Kankakee County
Established in 1853, Kankakee County has a population of about 110,000 residents. The county seat is Kankakee, and it is located in northeastern Illinois.
Kendall County
Established in 1841, Kendall County has a population of approximately 130,000 residents. The county seat is Yorkville, and it is located in northeastern Illinois.
Knox County
Established in 1825, Knox County has a population of around 49,000 residents. The county seat is Galesburg, and it is located in western Illinois.
Lake County
Established in 1839, Lake County has a population of about 703,000 residents. The county seat is Waukegan, and it is located in northeastern Illinois.
LaSalle County
Established in 1831, LaSalle County has a population of approximately 108,000 residents. The county seat is Ottawa, and it is located in north-central Illinois.
Lawrence County
Established in 1821, Lawrence County has a population of around 16,000 residents. The county seat is Lawrenceville, and it is located in southeastern Illinois.
Lee County
Established in 1839, Lee County has a population of approximately 34,000 residents. The county seat is Dixon, and it is located in north-central Illinois.
Livingston County
Established in 1837, Livingston County has a population of about 35,000 residents. The county seat is Pontiac, and it is located in east-central Illinois.
Logan County
Established in 1839, Logan County has a population of around 29,000 residents. The county seat is Lincoln, and it is located in central Illinois.
Macon County
Established in 1829, Macon County has a population of approximately 105,000 residents. The county seat is Decatur, and it is located in central Illinois.
Macoupin County
Established in 1829, Macoupin County has a population of around 45,000 residents. The county seat is Carlinville, and it is located in southwestern Illinois.
Madison County
Established in 1812, Madison County has a population of about 267,000 residents. The county seat is Edwardsville, and it is located in southwestern Illinois.
Marion County
Established in 1823, Marion County has a population of approximately 38,000 residents. The county seat is Salem, and it is located in southern Illinois.
Marshall County
Established in 1839, Marshall County has a population of around 11,000 residents. The county seat is Lacon, and it is located in north-central Illinois.
Mason County
Established in 1841, Mason County has a population of about 13,000 residents. The county seat is Havana, and it is located in central Illinois.
Massac County
Established in 1843, Massac County has a population of approximately 14,000 residents. The county seat is Metropolis, and it is located in southern Illinois.
McDonough County
Established in 1826, McDonough County has a population of around 30,000 residents. The county seat is Macomb, and it is located in western Illinois.
McHenry County
Established in 1836, McHenry County has a population of about 307,000 residents. The county seat is Woodstock, and it is located in northeastern Illinois.
McLean County
Established in 1830, McLean County has a population of approximately 172,000 residents. The county seat is Bloomington, and it is located in central Illinois.
Menard County
Established in 1839, Menard County has a population of around 12,000 residents. The county seat is Petersburg, and it is located in central Illinois.
Mercer County
Established in 1825, Mercer County has a population of about 15,000 residents. The county seat is Aledo, and it is located in northwestern Illinois.
Monroe County
Established in 1816, Monroe County has a population of approximately 36,000 residents. The county seat is Waterloo, and it is located in southwestern Illinois.
Montgomery County
Established in 1821, Montgomery County has a population of around 28,000 residents. The county seat is Hillsboro, and it is located in central Illinois.
Morgan County
Established in 1823, Morgan County has a population of about 34,000 residents. The county seat is Jacksonville, and it is located in central Illinois.
Moultrie County
Established in 1843, Moultrie County has a population of approximately 14,000 residents. The county seat is Sullivan, and it is located in central Illinois.
Ogle County
Established in 1836, Ogle County has a population of around 50,000 residents. The county seat is Oregon, and it is located in north-central Illinois.
Peoria County
Established in 1825, Peoria County has a population of approximately 179,000 residents. The county seat is Peoria, and it is located in central Illinois.
Perry County
Established in 1827, Perry County has a population of about 21,000 residents. The county seat is Pinckneyville, and it is located in southern Illinois.
Piatt County
Established in 1841, Piatt County has a population of around 16,000 residents. The county seat is Monticello, and it is located in central Illinois.
Pike County
Established in 1821, Pike County has a population of approximately 15,000 residents. The county seat is Pittsfield, and it is located in western Illinois.
Pope County
Established in 1816, Pope County has a population of around 4,000 residents. The county seat is Golconda, and it is located in southern Illinois.
Pulaski County
Established in 1843, Pulaski County has a population of about 5,000 residents. The county seat is Mound City, and it is located in southern Illinois.
Putnam County
Established in 1825, Putnam County has a population of approximately 5,000 residents. The county seat is Hennepin, and it is located in north-central Illinois.
Randolph County
Established in 1795, Randolph County has a population of around 32,000 residents. The county seat is Chester, and it is located in southern Illinois.
Richland County
Established in 1841, Richland County has a population of about 16,000 residents. The county seat is Olney, and it is located in southeastern Illinois.
Rock Island County
Established in 1831, Rock Island County has a population of approximately 142,000 residents. The county seat is Rock Island, and it is located in northwestern Illinois.
St. Clair County
Established in 1790, St. Clair County has a population of around 259,000 residents. The county seat is Belleville, and it is located in southwestern Illinois.
Saline County
Established in 1847, Saline County has a population of about 24,000 residents. The county seat is Harrisburg, and it is located in southern Illinois.
Sangamon County
Established in 1821, Sangamon County has a population of approximately 197,000 residents. The county seat is Springfield, and it is located in central Illinois.
Schuyler County
Established in 1825, Schuyler County has a population of around 6,000 residents. The county seat is Rushville, and it is located in western Illinois.
Scott County
Established in 1839, Scott County has a population of about 4,000 residents. The county seat is Winchester, and it is located in western Illinois.
Shelby County
Established in 1827, Shelby County has a population of approximately 22,000 residents. The county seat is Shelbyville, and it is located in central Illinois.
Stark County
Established in 1839, Stark County has a population of around 5,000 residents. The county seat is Toulon, and it is located in north-central Illinois.
Stephenson County
Established in 1837, Stephenson County has a population of about 44,000 residents. The county seat is Freeport, and it is located in northwestern Illinois.
Tazewell County
Established in 1827, Tazewell County has a population of approximately 133,000 residents. The county seat is Pekin, and it is located in central Illinois.
Union County
Established in 1818, Union County has a population of around 17,000 residents. The county seat is Jonesboro, and it is located in southern Illinois.
Vermilion County
Established in 1826, Vermilion County has a population of approximately 75,000 residents. The county seat is Danville, and it is located in eastern Illinois.
Wabash County
Established in 1824, Wabash County has a population of about 11,000 residents. The county seat is Mount Carmel, and it is located in southeastern Illinois.
Warren County
Established in 1825, Warren County has a population of around 16,000 residents. The county seat is Monmouth, and it is located in northwestern Illinois.
Washington County
Established in 1818, Washington County has a population of approximately 13,000 residents. The county seat is Nashville, and it is located in southwestern Illinois.
Wayne County
Established in 1819, Wayne County has a population of about 16,000 residents. The county seat is Fairfield, and it is located in southeastern Illinois.
White County
Established in 1815, White County has a population of around 13,000 residents. The county seat is Carmi, and it is located in southeastern Illinois.
Whiteside County
Established in 1836, Whiteside County has a population of approximately 55,000 residents. The county seat is Morrison, and it is located in northwestern Illinois.
Will County
Established in 1836, Will County has a population of around 700,000 residents, making it one of the most populous counties in the state. The county seat is Joliet, and it is located in northeastern Illinois.
Williamson County
Established in 1839, Williamson County has a population of about 66,000 residents. The county seat is Marion, and it is located in southern Illinois.
Winnebago County
Established in 1836, Winnebago County has a population of approximately 282,000 residents. The county seat is Rockford, and it is located in northern Illinois.
Woodford County
Established in 1841, Woodford County has a population of around 38,000 residents. The county seat is Eureka, and it is located in central Illinois.
Old Antique Atlases & Maps of Illinois
Disclaimer: All Illinois maps are free to use for your own genealogical purposes and may not be reproduced for resale or distribution.
Source: David Rumsey Historical Map Collection
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1776 Mississipi River
1776 Course Of The River Mississipi, from the Balise to Fort Chartres Atlas Map
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1822 Illinois
1822 Geographical, Historical, And Statistical Atlas Map Of Illinois
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1827 Map of Illinois
Map of the Illinois, Ohio & Indiana and Part of the Michigan Territory
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1836 Atlas Map Of Illinois
1836 A New Atlas Map Of Illinois With Its Proposed Canals, Roads & Distances from place to place, along the Stage & Steam Boat Routes
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1845 Atlas Map of Illinois
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1856 Atlas Map of Illinois
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1856 City of Chigago, Illinois
1856 City Of St. Louis Missouri. (with) The City Of Chicago Illinois Atlas Map
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1866 Map of the State of Illinois
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1880 Illinois
1880 County & township map of the state of Illinois with Vicinity of Springfield
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1880 Map of Chicago
D.O.T. County Road and Highway Maps of Illinois
To View the Map: Just click the image to view the map online. In order to make the image size as small as possible, they were saved on the lowest resolution.
Illinois Map Links
- Illinois State Park Map (mapofus.org)
- Illinois Lakes and Rivers Map (mapofus.org)
- U.S., Indexed County Land Ownership Maps, 1860-1918 (ancestry.com)
- Old Historical Maps of Illinois (alabamamaps.ua.edu)
- Illinois Maps, Atlases & Gazetteers (ancestry.com)
- Illinois Digital Map Library (usgwarchives.net)
- Illinois Maps – The Perry-Castañeda Library Map Collection (lib.utexas.edu)
- American Memory Map Collection: 1500-2004 (memory.loc.gov)
- Illinois USGenWeb Archives Digital Map Library (usgwarchives.net)
- Federal Township Plats of Illinois (1804-1891) (landplats.ilsos.net)
- Illinois Map Books (amazon.com)
