Illinois County Map, List of Counties in Illinois and Seats

The U.S. state of Illinois is divided into 102 Counties. Explore the Illinois County Map, all Counties list along with their County Seats in alphabetical order and their population, areas and the date of formation.

Illinois County Map

Illinois County Map About Illinois County Map: The map showing the county boundary, all counties boundary, state capital and neighbouring states.

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Illinois Area CodesIllinois Blank MapIllinois River Map
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About Counties of Illinois

Illinois is a state of United States which is located in the Midwestern region of the county. The state ranks as the largest state in terms of population. The state occupies an arena of 55519 square miles that accounts for 143793 square kilometers in the country. The capital city of the state is Springfield. The state Illinois is surrounded with other states namely Wisconsin is located to the north of the state where as Iowa and Missouri to the west, Kentucky to the east and south, and Indiana to the east. The state is blessed with many natural resources like coal, timber, petroleum and fertile soil. Illinois is nicknamed as ‘The Prairie State’. The state has another nick name too ‘Land of Lincoln’.

The state takes privilege of having big cities. The prominent cities of the state are Chicago, Aurora, Rockford and Springfield. Chicago is the largest city in the state of Illinois which is most populated city with 2,679,080 million citizens. Aurora and Naperville stood as second and third largest cities of the state in terms of population. Pingree Grove has been considered as the fastest growing city in the state.

There are 102 counties in the state of Illinois. Cook County in fact is the biggest county regarding population and the smallest county in terms of population is Hardin County. Geographically the biggest County is McLean County and Putnam County is the smallest. According the constitution of Illinois the state government entitled to have three branches of administration; they are executive branch, legislative branch and Judicial branch. As per home rule county is governed by a body of Commissioners. The Commissioners and the president of a County Board are usually elected.

The U.S. state of Illinois has 102 Counties. This is list of Illinois Counties and County Seats in alphabetical order along with check their population, areas and the date of formation.

List of Counties in Illinois and County Seats

Click on any County for Its detailed Map and Info.
S.NCountyCounty SeatPopulationAreaFormed
1Adams CountyQuincy67,103857 sq mi1,825
2Alexander CountyCairo8,238236 sq mi1,819
3Bond CountyGreenville17,768380 sq mi1,817
4Boone CountyBelvidere54,165281 sq mi1,837
5Brown CountyMount Sterling6,937306 sq mi1,839
6Bureau CountyPrinceton34,978869 sq mi1,837
7Calhoun CountyHardin5,089254 sq mi1,825
8Carroll CountyMount Carroll15,387444 sq mi1,839
9Cass CountyVirginia13,642376 sq mi1,837
10Champaign CountyUrbana201,081997 sq mi1,833
11Christian CountyTaylorville34,800709 sq mi1,839
12Clark CountyMarshall16,335502 sq mi1,819
13Clay CountyLouisville13,815469 sq mi1,824
14Clinton CountyCarlyle37,762474 sq mi1,824
15Coles CountyCharleston53,873508 sq mi1,830
16Cook CountyChicago5,194,675946 sq mi1,831
17Crawford CountyRobinson19,817444 sq mi1,816
18Cumberland CountyToledo11,048346 sq mi1,843
19DeKalb CountySycamore105,160634 sq mi1,837
20DeWitt CountyClinton16,561398 sq mi1,839
21Douglas CountyTuscola19,980417 sq mi1,859
22DuPage CountyWheaton916,924334 sq mi1,839
23Edgar CountyParis18,576624 sq mi1,823
24Edwards CountyAlbion6,721222 sq mi1,814
25Effingham CountyEffingham34,242479 sq mi1,831
26Fayette CountyVandalia22,140716 sq mi1,821
27Ford CountyPaxton14,081486 sq mi1,859
28Franklin CountyBenton39,561412 sq mi1,818
29Fulton CountyLewistown37,069866 sq mi1,823
30Gallatin CountyShawneetown5,589324 sq mi1,812
31Greene CountyCarrollton13,886543 sq mi1,821
32Grundy CountyMorris50,063420 sq mi1,841
33Hamilton CountyMcLeansboro8,457435 sq mi1,821
34Hancock CountyCarthage19,104795 sq mi1,825
35Hardin CountyElizabethtown4,320178 sq mi1,839
36Henderson CountyOquawka7,331379 sq mi1,841
37Henry CountyCambridge50,486823 sq mi1,825
38Iroquois CountyWatseka29,7181,116 sq mi1,833
39Jackson CountyMurphysboro60,218588 sq mi1,816
40Jasper CountyNewton9,698494 sq mi1,831
41Jefferson CountyMount Vernon38,827571 sq mi1,819
42Jersey CountyJerseyville22,985369 sq mi1,839
43Jo Daviess CountyGalena22,678601 sq mi1,827
44Johnson CountyVienna12,582346 sq mi1,812
45Kane CountyGeneva515,269521 sq mi1,836
46Kankakee CountyKankakee113,449678 sq mi1,853
47Kendall CountyYorkville114,736321 sq mi1,841
48Knox CountyGalesburg52,919716 sq mi1,825
49Lake CountyWaukegan703,462448 sq mi1,839
50LaSalle CountyOttawa113,9241,135 sq mi1,831
51Lawrence CountyLawrenceville16,833372 sq mi1,821
52Lee CountyDixon36,031725 sq mi1,839
53Livingston CountyPontiac38,9501,044 sq mi1,837
54Logan CountyLincoln30,305618 sq mi1,839
55Macon CountyDecatur110,768581 sq mi1,829
56Macoupin CountyCarlinville47,765864 sq mi1,829
57Madison CountyEdwardsville269,282725 sq mi1,812
58Marion CountySalem39,437572 sq mi1,823
59Marshall CountyLacon12,640386 sq mi1,839
60Mason CountyHavana14,666539 sq mi1,841
61Massac CountyMetropolis15,429239 sq mi1,843
62McDonough CountyMacomb32,612589 sq mi1,826
63McHenry CountyWoodstock308,760604 sq mi1,836
64McLean CountyBloomington169,5721,184 sq mi1,830
65Menard CountyPetersburg12,705314 sq mi1,839
66Mercer CountyAledo16,434561 sq mi1,825
67Monroe CountyWaterloo32,957388 sq mi1,816
68Montgomery CountyHillsboro30,104704 sq mi1,821
69Morgan CountyJacksonville35,547569 sq mi1,823
70Moultrie CountySullivan14,846336 sq mi1,843
71Ogle CountyOregon53,497759 sq mi1,836
72Peoria CountyPeoria186,494620 sq mi1,825
73Perry CountyPinckneyville22,350441 sq mi1,827
74Piatt CountyMonticello16,729440 sq mi1,841
75Pike CountyPittsfield16,430830 sq mi1,821
76Pope CountyGolconda4,470371 sq mi1,816
77Pulaski CountyMound City6,161201 sq mi1,843
78Putnam CountyHennepin6,006160 sq mi1,825
79Randolph CountyChester33,476578 sq mi1,795
80Richland CountyOlney16,233360 sq mi1,841
81Rock Island CountyRock Island147,546427 sq mi1,831
82Saline CountyHarrisburg24,913383 sq mi1,847
83Sangamon CountySpringfield197,465868 sq mi1,821
84Schuyler CountyRushville7,544437 sq mi1,825
85Scott CountyWinchester5,355251 sq mi1,839
86Shelby CountyShelbyville22,363759 sq mi1,827
87St Clair CountyBelleville270,056664 sq mi1,790
88Stark CountyToulon5,994288 sq mi1,839
89Stephenson CountyFreeport47,711564 sq mi1,837
90Tazewell CountyPekin135,394649 sq mi1,827
91Union CountyJonesboro17,808416 sq mi1,818
92Vermilion CountyDanville81,625899 sq mi1,826
93Wabash CountyMount Carmel11,947224 sq mi1,824
94Warren CountyMonmouth17,707543 sq mi1,825
95Washington CountyNashville14,716563 sq mi1,818
96Wayne CountyFairfield16,760714 sq mi1,819
97White CountyCarmi14,665495 sq mi1,815
98Whiteside CountyMorrison58,498685 sq mi1,836
99Will CountyJoliet677,560837 sq mi1,836
100Williamson CountyMarion66,357424 sq mi1,839
101Winnebago CountyRockford295,266514 sq mi1,836
102Woodford CountyEureka38,664528 sq mi1,841
Edited by: Vijay Kanth | Updated on: October 25, 2022