List of counties in Illinois

There are 102 counties in the state of Illinois

Most counties in Illinois were named after early American leaders, especially of the American Revolutionary War, as well as soldiers from the Battle of Tippecanoe and the War of 1812 Some are named after natural features or counties in other states Some are named for early Illinois leaders Two counties are named for Native American tribes, and one bears the name of a plant used as a food source by Native Americans

While it does have a city, Illinois does not have a Lincoln County named after its favorite son, Abraham Lincoln; it does, however, have a Douglas County founded 1859 named after his political rival Stephen A Douglas It also has Calhoun County founded 1825, named after John C Calhoun, outspoken for his pro-slavery and pro-southern views in the years preceding the American Civil War Several of the counties are named after Southerners, reflecting the fact that Illinois was for a short time part of Virginia, and settled in its early years by many Southerners No counties are named after Northern heroes of the Civil War, mainly because the counties were all named before that war The state does have a Lee County named after the family of Robert E Lee, who at one time served in Illinois Illinois also has two counties named after the same person, New York governor DeWitt Clinton this may be unusual, but it is not unprecedented since Virginia has had two counties named after Patrick Henry since 1790

Information on the FIPS county code, county seat, year of establishment, origin, etymology, population, area and map of each county is included in the table below

Illinois's postal abbreviation is IL and its FIPS state code is 17

1 Counties
2 Defunct counties
3 See also
4 Notes
5 References
6 External links

Countiesedit

Note: the links in the FIPS County Code column are to the Census Bureau info page for that county

County	FIPS County Code 1	County seat 2	Established 2	Origin	Etymology34	Population 2	Area 2
Adams County	001	Quincy	1825	Pike County	John Quincy Adams 1767–1848, sixth President of the United States	7004671030000000000♠67,103	7002857000000000000♠857 sq mi 7003222000000000000♠2,220 km2
Alexander County	003	Cairo	1819	Union County	William M Alexander, settler and state representative in the Illinois General Assembly	7003823800000000000♠8,238	7002236000000000000♠236 sq mi 7002611000000000000♠611 km2
Bond County	005	Greenville	1817	Crawford County, Edwards County, and Madison County	Shadrach Bond 1773–1832, first Governor of Illinois	7004177680000000000♠17,768	7002380000000000000♠380 sq mi 7002984000000000000♠984 km2
Boone County	007	Belvidere	1837	Winnebago County	Daniel Boone 1734–1820, trailblazer of the Wilderness Road in Kentucky	7004541650000000000♠54,165	7002281000000000000♠281 sq mi 7002728000000000000♠728 km2
Brown County	009	Mount Sterling	1839	Schuyler County	Jacob Brown 1775–1828, successful War of 1812 army officer responsible for Great Lakes defenses	7003693700000000000♠6,937	7002306000000000000♠306 sq mi 7002793000000000000♠793 km2
Bureau County	011	Princeton	1837	Putnam County	Pierre de Bureo, Frenchman, North American fur trader	7004349780000000000♠34,978	7002869000000000000♠869 sq mi 7003225100000000000♠2,251 km2
Calhoun County	013	Hardin	1825	Pike County	John C Calhoun 1782–1850, South Carolina senator and seventh Vice President of the United States	7003508900000000000♠5,089	7002254000000000000♠254 sq mi 7002658000000000000♠658 km2
Carroll County	015	Mount Carroll	1839	Jo Daviess	Charles Carroll of Carrollton 1737–1832, signed the Declaration of Independence on behalf of Maryland	7004153870000000000♠15,387	7002444000000000000♠444 sq mi 7003115000000000000♠1,150 km2
Cass County	017	Virginia	1837	Morgan County	Lewis Cass 1782–1866, second governor of Michigan Territory, fourteenth United States Secretary of War	7004136420000000000♠13,642	7002376000000000000♠376 sq mi 7002974000000000000♠974 km2
Champaign County	019	Urbana	1833	Vermilion County	Champaign County, Ohio, which took its name from the French for "open level country"	7005201081000000000♠201,081	7002997000000000000♠997 sq mi 7003258200000000000♠2,582 km2
Christian County	021	Taylorville	1839	Sangamon County	Christian County, Kentucky, which was itself named after Colonel William Christian	7004348000000000000♠34,800	7002709000000000000♠709 sq mi 7003183600000000000♠1,836 km2
Clark County	023	Marshall	1819	Crawford County	George Rogers Clark 1752–1818, highest-ranking officer in the Northwest Territory during the American Revolution	7004163350000000000♠16,335	7002502000000000000♠502 sq mi 7003130000000000000♠1,300 km2
Clay County	025	Louisville	1824	Wayne, Lawrence, Fayette, and Crawford County	Henry Clay 1777–1852, Kentucky legislator who negotiated the Missouri Compromise	7004138150000000000♠13,815	7002469000000000000♠469 sq mi 7003121500000000000♠1,215 km2
Clinton County	027	Carlyle	1824	Washington, Bond, and Fayette County	DeWitt Clinton 1769–1828, Governor of New York, responsible for the construction of the Erie Canal	7004377620000000000♠37,762	7002474000000000000♠474 sq mi 7003122800000000000♠1,228 km2
Coles County	029	Charleston	1830	Clark and Edgar County	Edward Coles 1786–1868, second Governor of Illinois, responsible for the abolition of slavery in Illinois	7004538730000000000♠53,873	7002508000000000000♠508 sq mi 7003131600000000000♠1,316 km2
Cook County	031	Chicago	1831	Putnam County	Daniel Pope Cook 1794–1827, politician and first Attorney General of Illinois	7006519467500000000♠5,194,675	7002946000000000000♠946 sq mi 7003245000000000000♠2,450 km2
Crawford County	033	Robinson	1816	Edwards County	William H Crawford 1772–1834, ninth United States Secretary of War, seventh Secretary of the Treasury	7004198170000000000♠19,817	7002444000000000000♠444 sq mi 7003115000000000000♠1,150 km2
Cumberland County	035	Toledo	1843	Coles County	Disputed: Cumberland Road, which entered the county; Cumberland, Maryland; or Cumberland River in Kentucky	7004110480000000000♠11,048	7002346000000000000♠346 sq mi 7002896000000000000♠896 km2
DeKalb County	037	Sycamore	1837	Kane County	Johann de Kalb 1721–1780, German soldier in the Continental Army who fought alongside Gilbert du Motier, marquis de Lafayette	7005105160000000000♠105,160	7002634000000000000♠634 sq mi 7003164200000000000♠1,642 km2
DeWitt County	039	Clinton	1839	Macon and McLean County	DeWitt Clinton 1769–1828, Governor of New York, responsible for the construction of the Erie Canal	7004165610000000000♠16,561	7002398000000000000♠398 sq mi 7003103100000000000♠1,031 km2
Douglas County	041	Tuscola	1859	Coles County	Stephen A Douglas 1813–61, prominent Illinois Democrat who engaged in debates with Abraham Lincoln	7004199800000000000♠19,980	7002417000000000000♠417 sq mi 7003108000000000000♠1,080 km2
DuPage County	043	Wheaton	1839	Cook County	DuPage River	7005916924000000000♠916,924	7002334000000000000♠334 sq mi 7002865000000000000♠865 km2
Edgar County	045	Paris	1823	Clark County	John Edgar c 1750–1832, Illinois delegate to the Northwest Territory legislature; at the time, wealthiest man in Illinois	7004185760000000000♠18,576	7002624000000000000♠624 sq mi 7003161600000000000♠1,616 km2
Edwards County	047	Albion	1814	Gallatin County and Madison County	Ninian Edwards 1775–1833, third Governor of the State of Illinois and only governor of the Illinois Territory	7003672100000000000♠6,721	7002222000000000000♠222 sq mi 7002575000000000000♠575 km2
Effingham County	049	Effingham	1831	Fayette and Crawford County	Thomas Howard, 3rd Earl of Effingham, military officer who resigned from the British Army to avoid fighting the American colonies	7004342420000000000♠34,242	7002479000000000000♠479 sq mi 7003124100000000000♠1,241 km2
Fayette County	051	Vandalia	1821	Bond, Wayne, Clark, Jefferson, and Crawford County	Gilbert du Motier, marquis de Lafayette 1757–1834, French military officer who was a key factor in the American and French Revolutions	7004221400000000000♠22,140	7002716000000000000♠716 sq mi 7003185400000000000♠1,854 km2
Ford County	053	Paxton	1859	Vermilion County	Thomas Ford 1800–50, eighth Governor of Illinois; served during the Illinois Mormon War	7004140810000000000♠14,081	7002486000000000000♠486 sq mi 7003125900000000000♠1,259 km2
Franklin County	055	Benton	1818	White County and Gallatin County	Benjamin Franklin 1706–90, prolific writer, inventor, and politician; key factor in the American Revolution	7004395610000000000♠39,561	7002412000000000000♠412 sq mi 7003106700000000000♠1,067 km2
Fulton County	057	Lewistown	1823	Pike County	Robert Fulton 1765–1815, inventor of the steamboat	7004370690000000000♠37,069	7002866000000000000♠866 sq mi 7003224300000000000♠2,243 km2
Gallatin County	059	Shawneetown	1812	Randolph County	Albert Gallatin 1761–1849, fourth and longest-serving United States Secretary of the Treasury	7003558900000000000♠5,589	7002324000000000000♠324 sq mi 7002839000000000000♠839 km2
Greene County	061	Carrollton	1821	Madison County	Nathanael Greene 1742–86, major general in the Continental Army	7004138860000000000♠13,886	7002543000000000000♠543 sq mi 7003140600000000000♠1,406 km2
Grundy County	063	Morris	1841	LaSalle County	Felix Grundy 1777–1840, Tennessean senator who served as the thirteenth United States Attorney General	7004500630000000000♠50,063	7002420000000000000♠420 sq mi 7003108800000000000♠1,088 km2
Hamilton County	065	McLeansboro	1821	White County	Alexander Hamilton 1755–1804, first United States Secretary of the Treasury	7003845700000000000♠8,457	7002435000000000000♠435 sq mi 7003112700000000000♠1,127 km2
Hancock County	067	Carthage	1825	Adams County	John Hancock 1737–93, first governor of the Massachusetts colony and president of the Second Continental Congress	7004191040000000000♠19,104	7002795000000000000♠795 sq mi 7003205900000000000♠2,059 km2
Hardin County	069	Elizabethtown	1839	Pope County	Hardin County, Kentucky, which was itself named after John Hardin	7003432000000000000♠4,320	7002178000000000000♠178 sq mi 7002461000000000000♠461 km2
Henderson County	071	Oquawka	1841	Warren County	Henderson County, Kentucky, which was itself named after Richard Henderson	7003733100000000000♠7,331	7002379000000000000♠379 sq mi 7002982000000000000♠982 km2
Henry County	073	Cambridge	1825	Fulton County	Patrick Henry 1736-99, American Revolutionary War figure; first and sixth Governor of Virginia	7004504860000000000♠50,486	7002823000000000000♠823 sq mi 7003213200000000000♠2,132 km2
Iroquois County	075	Watseka	1833	Vermilion County	Iroquois Native Americans	7004297180000000000♠29,718	7003111600000000000♠1,116 sq mi 7003289000000000000♠2,890 km2
Jackson County	077	Murphysboro	1816	Randolph County and Johnson County	Andrew Jackson 1767–1845, seventh President of the United States, United States Senator from Tennessee, and general in the War of 1812	7004602180000000000♠60,218	7002588000000000000♠588 sq mi 7003152300000000000♠1,523 km2
Jasper County	079	Newton	1831	Clay and Crawford County	Sgt William Jasper c 1750-79, American Revolutionary War soldier popularized by Parson Weems	7003969800000000000♠9,698	7002494000000000000♠494 sq mi 7003127900000000000♠1,279 km2
Jefferson County	081	Mount Vernon	1819	Edwards and White County	Thomas Jefferson 1743–1826, third President of the United States, second Vice President of the United States, Governor of Virginia, and one of the foremost Founding Fathers of the United States	7004388270000000000♠38,827	7002571000000000000♠571 sq mi 7003147900000000000♠1,479 km2
Jersey County	083	Jerseyville	1839	Greene County	State of New Jersey, from which many early settlers hailed	7004229850000000000♠22,985	7002369000000000000♠369 sq mi 7002956000000000000♠956 km2
Jo Daviess County	085	Galena	1827	Henry, Mercer, and Putnam County	Joseph Hamilton Daveiss 1774–1811, commander of the Indiana Dragoons at the Battle of Tippecanoe	7004226780000000000♠22,678	7002601000000000000♠601 sq mi 7003155700000000000♠1,557 km2
Johnson County	087	Vienna	1812	Randolph County	Richard Mentor Johnson abt 1780-1850, ninth Vice President of the United States and United States Senator from Kentucky	7004125820000000000♠12,582	7002346000000000000♠346 sq mi 7002896000000000000♠896 km2
Kane County	089	Geneva	1836	LaSalle County	Elias Kane 1794–1835, United States Senator from Illinois	7005515269000000000♠515,269	7002521000000000000♠521 sq mi 7003134900000000000♠1,349 km2
Kankakee County	091	Kankakee	1853	Iroquois and Will County	Kankakee River	7005113449000000000♠113,449	7002678000000000000♠678 sq mi 7003175600000000000♠1,756 km2
Kendall County	093	Yorkville	1841	LaSalle and Kane County	Amos Kendall 1789–1869, United States Postmaster General under Presidents Andrew Jackson and Martin Van Buren	7005114736000000000♠114,736	7002321000000000000♠321 sq mi 7002831000000000000♠831 km2
Knox County	095	Galesburg	1825	Fulton County	Gen Henry Knox 1750–1806, American Revolutionary War general and first United States Secretary of War	7004529190000000000♠52,919	7002716000000000000♠716 sq mi 7003185400000000000♠1,854 km2
Lake County	097	Waukegan	1839	McHenry County	Lake Michigan	7005703462000000000♠703,462	7002448000000000000♠448 sq mi 7003116000000000000♠1,160 km2
LaSalle County	099	Ottawa	1831	Putnam and Tazewell County	Sieur de la Salle 1643-87, French explorer of the Great Lakes	7005113924000000000♠113,924	7003113500000000000♠1,135 sq mi 7003294000000000000♠2,940 km2
Lawrence County	101	Lawrenceville	1821	Crawford and Edwards County	Capt James Lawrence 1781–1813, commander of the USS Chesapeake in the War of 1812 Famous for his command "Don't give up the ship!"	7004168330000000000♠16,833	7002372000000000000♠372 sq mi 7002963000000000000♠963 km2
Lee County	103	Dixon	1839	Ogle County	"Light Horse" Henry Lee III 1756–1818, American Revolutionary War officer and ninth Governor of Virginia	7004360310000000000♠36,031	7002725000000000000♠725 sq mi 7003187800000000000♠1,878 km2
Livingston County	105	Pontiac	1837	LaSalle and McLean County	Edward Livingston 1764–1836, prominent jurist, Congressman from New York and Louisiana, and US Secretary of State from 1831-33	7004389500000000000♠38,950	7003104400000000000♠1,044 sq mi 7003270400000000000♠2,704 km2
Logan County	107	Lincoln	1839	Sangamon County	John Logan, country doctor and early settler, and the father of John A Logan	7004303050000000000♠30,305	7002618000000000000♠618 sq mi 7003160100000000000♠1,601 km2
Macon County	115	Decatur	1829	Shelby County	Nathaniel Macon 1758–1837, sixth Speaker of the United States House of Representatives and United States Senator from North Carolina	7005110768000000000♠110,768	7002581000000000000♠581 sq mi 7003150500000000000♠1,505 km2
Macoupin County	117	Carlinville	1829	Greene County	Native American word macoupin, meaning "American lotus"	7004477650000000000♠47,765	7002864000000000000♠864 sq mi 7003223800000000000♠2,238 km2
Madison County	119	Edwardsville	1812	St Clair County and Randolph County	James Madison 1751–1836, fourth President of the United States and principal author of the Constitution of the United States	7005269282000000000♠269,282	7002725000000000000♠725 sq mi 7003187800000000000♠1,878 km2
Marion County	121	Salem	1823	Fayette and Jefferson County	Francis Marion c 1732-95, general in the American Revolutionary War known as "The Swamp Fox"	7004394370000000000♠39,437	7002572000000000000♠572 sq mi 7003148100000000000♠1,481 km2
Marshall County	123	Lacon	1839	Putnam County	John Marshall 1755–1835, fourth and longest-serving Chief Justice of the United States, wrote opinion in Marbury v Madison establishing the principle of judicial review	7004126400000000000♠12,640	7002386000000000000♠386 sq mi 7003100000000000000♠1,000 km2
Mason County	125	Havana	1841	Tazewell and Menard County	Named after Mason County, Kentucky, itself named after George Mason	7004146660000000000♠14,666	7002539000000000000♠539 sq mi 7003139600000000000♠1,396 km2
Massac County	127	Metropolis	1843	Pope and Johnson County	Fort Massac, a colonial-era fort on the Ohio River	7004154290000000000♠15,429	7002239000000000000♠239 sq mi 7002619000000000000♠619 km2
McDonough County	109	Macomb	1826	Schuyler County	Commodore Thomas Macdonough 1783–1825, commander of American naval forces at the Battle of Plattsburgh	7004326120000000000♠32,612	7002589000000000000♠589 sq mi 7003152600000000000♠1,526 km2
McHenry County	111	Woodstock	1836	Cook and LaSalle County	Major William McHenry c 1771 – 1835, officer in during several campaigns against Native Americans and member of the Illinois legislature	7005308760000000000♠308,760	7002604000000000000♠604 sq mi 7003156400000000000♠1,564 km2
McLean County	113	Bloomington	1830	Tazewell County	John McLean 1791–1830, United States Representative and United States Senator from Illinois the latter from 1824-25 and 1829-30	7005169572000000000♠169,572	7003118400000000000♠1,184 sq mi 7003306700000000000♠3,067 km2
Menard County	129	Petersburg	1839	Sangamon County	Pierre Menard 1766–1844, prominent early settler and first Lieutenant Governor of Illinois	7004127050000000000♠12,705	7002314000000000000♠314 sq mi 7002813000000000000♠813 km2
Mercer County	131	Aledo	1825	Schuyler County	Hugh Mercer 1726-77, British officer in the Seven Years' War and general in the Continental Army during the American Revolutionary War	7004164340000000000♠16,434	7002561000000000000♠561 sq mi 7003145300000000000♠1,453 km2
Monroe County	133	Waterloo	1816	Randolph County and St Clair County	James Monroe 1758–1831, seventh United States Secretary of State, eighth United States Secretary of War, Governor of Virginia, and fifth President of the United States	7004329570000000000♠32,957	7002388000000000000♠388 sq mi 7003100500000000000♠1,005 km2
Montgomery County	135	Hillsboro	1821	Bond and Madison County	Gen Richard Montgomery 1738-75, brigadier-general in the Continental Army who led the unsuccessful invasion of Canada	7004301040000000000♠30,104	7002704000000000000♠704 sq mi 7003182300000000000♠1,823 km2
Morgan County	137	Jacksonville	1823	Sangamon County	Gen Daniel Morgan 1736–1802, successful tactician in the American Revolutionary War and later United States Representative from Virginia	7004355470000000000♠35,547	7002569000000000000♠569 sq mi 7003147400000000000♠1,474 km2
Moultrie County	139	Sullivan	1843	Shelby and Macon County	Gen William Moultrie 1730–1805, American Revolutionary War general and Governor of South Carolina	7004148460000000000♠14,846	7002336000000000000♠336 sq mi 7002870000000000000♠870 km2
Ogle County	141	Oregon	1836	Jo Daviess	Joseph Ogle 1737–1821, early settler in southwest Illinois, who helped found the first Methodist church in Illinois	7004534970000000000♠53,497	7002759000000000000♠759 sq mi 7003196600000000000♠1,966 km2
Peoria County	143	Peoria	1825	Fulton County	The Peoria Native American tribe	7005186494000000000♠186,494	7002620000000000000♠620 sq mi 7003160600000000000♠1,606 km2
Perry County	145	Pinckneyville	1827	Randolph and Jackson County	Commodore Oliver Hazard Perry 1785–1819, American naval officer who led the victorious American forces at the Battle of Lake Erie	7004223500000000000♠22,350	7002441000000000000♠441 sq mi 7003114200000000000♠1,142 km2
Piatt County	147	Monticello	1841	DeWitt and Macon County	John Piatt, the patriarch of a prominent settler family in the early history of the county	7004167290000000000♠16,729	7002440000000000000♠440 sq mi 7003114000000000000♠1,140 km2
Pike County	149	Pittsfield	1821	Madison, Bond, and Clark County	Zebulon Pike 1779–1813, early explorer of the American Southwest, namesake of Pikes Peak	7004164300000000000♠16,430	7002830000000000000♠830 sq mi 7003215000000000000♠2,150 km2
Pope County	151	Golconda	1816	Gallatin and Johnson County	Nathaniel Pope 1784–1850, early Delegate from Illinois Territory to Congress and judge on the United States District Court for the District of Illinois	7003447000000000000♠4,470	7002371000000000000♠371 sq mi 7002961000000000000♠961 km2
Pulaski County	153	Mound City	1843	Alexander and Johnson County	Gen Casimir Pulaski 1745-79, Polish American general of cavalry in the American Revolutionary War	7003616100000000000♠6,161	7002201000000000000♠201 sq mi 7002521000000000000♠521 km2
Putnam County	155	Hennepin	1825	Fulton County	Gen Israel Putnam 1718-90, commander of American forces at the Battle of Bunker Hill	7003600600000000000♠6,006	7002160000000000000♠160 sq mi 7002414000000000000♠414 km2
Randolph County	157	Chester	1795	St Clair County	Edmund Randolph 1753–1813, first Attorney General of the United States, and briefly United States Secretary of State	7004334760000000000♠33,476	7002578000000000000♠578 sq mi 7003149700000000000♠1,497 km2
Richland County	159	Olney	1841	Clay and Lawrence County	Richland County, Ohio, itself named for its rich soil	7004162330000000000♠16,233	7002360000000000000♠360 sq mi 7002932000000000000♠932 km2
Rock Island County	161	Rock Island	1831	Jo Daviess County	Rock Island	7005147546000000000♠147,546	7002427000000000000♠427 sq mi 7003110600000000000♠1,106 km2
Saline County	165	Harrisburg	1847	Gallatin County	Salt springs within the county	7004249130000000000♠24,913	7002383000000000000♠383 sq mi 7002992000000000000♠992 km2
Sangamon County	167	Springfield	1821	Madison and Bond County	Sangamon River	7005197465000000000♠197,465	7002868000000000000♠868 sq mi 7003224800000000000♠2,248 km2
Schuyler County	169	Rushville	1825	Pike and Fulton County	Gen Philip Schuyler 1733–1804, American Revolutionary War general and United States Senator from New York	7003754400000000000♠7,544	7002437000000000000♠437 sq mi 7003113200000000000♠1,132 km2
Scott County	171	Winchester	1839	Morgan County	Scott County, Kentucky, itself named after Charles Scott	7003535500000000000♠5,355	7002251000000000000♠251 sq mi 7002650000000000000♠650 km2
Shelby County	173	Shelbyville	1827	Fayette County	Isaac Shelby 1750–1826, soldier in the American Revolutionary War and War of 1812; first and fifth Governor of Kentucky	7004223630000000000♠22,363	7002759000000000000♠759 sq mi 7003196600000000000♠1,966 km2
St Clair County	163	Belleville	1790	original two counties	Arthur St Clair 1737–1818, major general in the American Revolutionary War and first Governor of the Northwest Territory	7005270056000000000♠270,056	7002664000000000000♠664 sq mi 7003172000000000000♠1,720 km2
Stark County	175	Toulon	1839	Knox and Putnam County	Gen John Stark 1728–1822, general in the American Revolutionary War, called the "Hero of Bennington"	7003599400000000000♠5,994	7002288000000000000♠288 sq mi 7002746000000000000♠746 km2
Stephenson County	177	Freeport	1837	Jo Daviess and Winnebago County	Benjamin Stephenson 1769–1822, representative of Illinois Territory in the United States Congress from 1814 to 1816	7004477110000000000♠47,711	7002564000000000000♠564 sq mi 7003146100000000000♠1,461 km2
Tazewell County	179	Pekin	1827	Sangamon County	Littleton Waller Tazewell 1774–1860, United States Senator from and later governor of Virginia	7005135394000000000♠135,394	7002649000000000000♠649 sq mi 7003168100000000000♠1,681 km2
Union County	181	Jonesboro	1818	Johnson County	The federal union of the states	7004178080000000000♠17,808	7002416000000000000♠416 sq mi 7003107700000000000♠1,077 km2
Vermilion County	183	Danville	1826	Edgar County	The Vermilion River	7004816250000000000♠81,625	7002899000000000000♠899 sq mi 7003232800000000000♠2,328 km2
Wabash County	185	Mount Carmel	1824	Edwards County	The Wabash River	7004119470000000000♠11,947	7002224000000000000♠224 sq mi 7002580000000000000♠580 km2
Warren County	187	Monmouth	1825	Schuyler County	Joseph Warren 1741-75, played a role in American Patriot movements, a prominent early fatality in the American Revolutionary War	7004177070000000000♠17,707	7002543000000000000♠543 sq mi 7003140600000000000♠1,406 km2
Washington County	189	Nashville	1818	St Clair County	George Washington 1732-99, commander-in-chief of American forces in the American Revolutionary War and first President of the United States	7004147160000000000♠14,716	7002563000000000000♠563 sq mi 7003145800000000000♠1,458 km2
Wayne County	191	Fairfield	1819	Edwards County	Gen "Mad" Anthony Wayne 1745-96, major general in the United States Army in the American Revolutionary War and the Northwest Indian War	7004167600000000000♠16,760	7002714000000000000♠714 sq mi 7003184900000000000♠1,849 km2
White County	193	Carmi	1815	Gallatin County	Isaac White 1776–1811, resident of Illinois who enlisted in the Indiana militia and was killed at the Battle of Tippecanoe	7004146650000000000♠14,665	7002495000000000000♠495 sq mi 7003128200000000000♠1,282 km2
Whiteside County	195	Morrison	1836	Jo Daviess and Henry County	Samuel Whiteside 1783–1868, state legislator and militia leader	7004584980000000000♠58,498	7002685000000000000♠685 sq mi 7003177400000000000♠1,774 km2
Will County	197	Joliet	1836	Cook and Iroquois County	Conrad Will 1779–1835,5 physician, local businessman and longtime member of the state legislature	7005677560000000000♠677,560	7002837000000000000♠837 sq mi 7003216800000000000♠2,168 km2
Williamson County	199	Marion	1839	Franklin County	Hugh Williamson 1735–1819, delegate from North Carolina to the Philadelphia Convention	7004663570000000000♠66,357	7002424000000000000♠424 sq mi 7003109800000000000♠1,098 km2
Winnebago County	201	Rockford	1836	Jo Daviess	Winnebago Native Americans	7005295266000000000♠295,266	7002514000000000000♠514 sq mi 7003133100000000000♠1,331 km2
Woodford County	203	Eureka	1841	Tazewell and McLean County	Gen William Woodford 1734-80, brigadier general in the American Revolutionary War who died while a British prisoner	7004386640000000000♠38,664	7002528000000000000♠528 sq mi 7003136800000000000♠1,368 km2

Defunct countiesedit

Dane County was renamed in 1840 to the current Christian County
The original Knox County, Illinois, became extinct with the formation of the Illinois Territory in 1809 - or, more precisely, it became Knox County, Indiana The modern Knox County, Illinois was formed much later and was not a part of the original Knox County

Notesedit

^ "EPA County FIPS Code Listing" EPAgov Retrieved 2008-02-23
^ a b c d "Find a county" National Association of Counties Retrieved 2012-09-26
^ "Illinois County Biographies" Genealogy Trailscom Genealogy Trails 2000 Retrieved 2008-09-21
^ "The Origin of Illinois County Names" Genealogy Trailscom Genealogy Trails 2000 Retrieved 2008-09-21
^ Matile, Roger 22 June 2006 "Reflections: Was Dr Conrad Will really worth his salt" Ledger-Sentinel Retrieved 11 October 2011

Referencesedit

Hébert, Michael L 2012 "Illinois County Boundaries: 1790 - Present" ILGenWeb
White, Jesse March 2010 "Origin and Evolution of Illinois Counties" PDF Illinois Secretary of State

External linksedit

Wikimedia Commons has media related to Counties in Illinois

Census 2000 US Gazetteer Files
Illinois Association of County Board Members
Illinois Association of County Officials
Illinois City/County Management Association

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