A
Adams County
County seat: Quincy
Alexander County
County seat: Cairo
B
Bond County
County seat: Greenville
Boone County
County seat: Belvidere
Brown County
County seat: Mount Sterling
Bureau County
County seat: Princeton
C
Calhoun County
County seat: Hardin
Carroll County
County seat: Mount Carroll
Cass County
County seat: Virginia
Champaign County
County seat: Urbana
Christian County
County seat: Taylorville
Clark County
County seat: Marshall
Clay County
County seat: Louisville
Clinton County
County seat: Carlyle
Coles County
County seat: Charleston
Cook County
County seat: Chicago
Crawford County
County seat: Robinson
Cumberland County
County seat: Toledo
D
DeKalb County
County seat: Sycamore
DeWitt County
County seat: Clinton
Douglas County
County seat: Tuscola
DuPage County
County seat: Wheaton
E
Edgar County
County seat: Paris
Edwards County
County seat: Albion
Effingham County
County seat: Effingham
F
Fayette County
County seat: Vandalia
Ford County
County seat: Paxton
Franklin County
County seat: Benton
Fulton County
County seat: Lewistown
G
Gallatin County
County seat: Shawneetown
Greene County
County seat: Carrollton
Grundy County
County seat: Morris
H
Hamilton County
County seat: McLeansboro
Hancock County
County seat: Carthage
Hardin County
County seat: Elizabethtown
Henderson County
County seat: Oquawka
Henry County
County seat: Cambridge
I
Iroquois County
County seat: Watseka
J
Jackson County
County seat: Murphysboro
Jasper County
County seat: Newton
Jefferson County
County seat: Mount Vernon
Jersey County
County seat: Jerseyville
Jo Daviess County
County seat: Galena
Johnson County
County seat: Vienna
K
Kane County
County seat: Geneva
Kankakee County
County seat: Kankakee
Kendall County
County seat: Yorkville
Knox County
County seat: Galesburg
L
Lake County
County seat: Waukegan
LaSalle County
County seat: Ottawa
Lawrence County
County seat: Lawrenceville
Lee County
County seat: Dixon
Livingston County
County seat: Pontiac
Logan County
County seat: Lincoln
M
Macon County
County seat: Decatur
Macoupin County
County seat: Carlinville
Madison County
County seat: Edwardsville
Marion County
County seat: Salem
Marshall County
County seat: Lacon
Mason County
County seat: Havana
Massac County
County seat: Metropolis
McDonough County
County seat: Macomb
McHenry County
County seat: Woodstock
McLean County
County seat: Bloomington
Menard County
County seat: Petersburg
Mercer County
County seat: Aledo
Monroe County
County seat: Waterloo
Montgomery County
County seat: Hillsboro
Morgan County
County seat: Jacksonville
Moultrie County
County seat: Sullivan
O
Ogle County
County seat: Oregon
P
Peoria County
County seat: Peoria
Perry County
County seat: Pinckneyville
Piatt County
County seat: Monticello
Pike County
County seat: Pittsfield
Pope County
County seat: Golconda
Pulaski County
County seat: Mound City
Putnam County
County seat: Hennepin
R
Randolph County
County seat: Chester
Richland County
County seat: Olney
Rock Island County
County seat: Rock Island
S
Saline County
County seat: Harrisburg
Sangamon County
County seat: Springfield
Schuyler County
County seat: Rushville
Scott County
County seat: Winchester
Shelby County
County seat: Shelbyville
Stark County
County seat: Toulon
St. Clair County
County seat: Belleville
Stephenson County
County seat: Freeport
T
Tazewell County
County seat: Pekin
U
Union County
County seat: Jonesboro
V
Vermilion County
County seat: Danville
W
Wabash County
County seat: Mount Carmel
Warren County
County seat: Monmouth
Washington County
County seat: Nashville
Wayne County
County seat: Fairfield
White County
County seat: Carmi
Whiteside County
County seat: Morrison
Will County
County seat: Joliet
Williamson County
County seat: Marion
Winnebago County
County seat: Rockford
Woodford County
County seat: Eureka