The Counties of Illinois

• Adams
• Alexander
• Bond
• Boone
• Brown
• Bureau
• Calhoun
• Carroll
• Cass
• Champaign
• Christian
• Clark
• Clay
• Clinton
• Coles
• Cook
• Crawford
• Cumberland
• DeKalb
• DeWitt
• Douglas
• DuPage
• Edgar
• Edwards
• Effingham
• Fayette

• Ford
• Franklin
• Fulton
• Gallatin
• Greene
• Grundy
• Hamilton
• Hancock
• Hardin
• Henderson
• Henry
• Iroquois
• Jackson
• Jasper
• Jefferson
• Jersey
• Jo Daviess
• Johnson
• Kane
• Kankakee
• Kendall
• Knox
• Lake
• LaSalle
• Lawrence
• Lee

• Livingston
• Logan
• Macon
• Macoupin
• Madison
• Marion
• Marshall
• Mason
• Massac
• McDonough
• McHenry
• McLean
• Menard
• Mercer
• Monroe
• Montgomery
• Morgan
• Moultrie
• Ogle
• Peoria
• Perry
• Piatt
• Pike
• Pope
• Pulaski
• Putnam

• Randolph
• Richland
• Rock Island
• Saint Clair
• Saline
• Sangamon
• Schuyler
• Scott
• Shelby
• Stark
• Stephenson
• Tazewell
• Union
• Vermilion
• Wabash
• Warren
• Washington
• Wayne
• White
• Whiteside
• Will
• Williamson
• Winnebago
• Woodford

• Regional: United States: Illinois: Cities 

• Illinois County Boundaries 1790 - Present  - Clickable maps show Illinois boundaries and each year new counties were added.