Champaign Region
Counties: Champaign, Clark, Coles, Cumberland, DeWitt, Douglas, Edgar, Ford, Iroquois, Livingston, Piatt, Macon, McLean, Moultrie, Shelby, Vermilion

Chicago Region
County: Cook

Edwardsville Region
Counties: Bond, Calhoun, Christian, Clinton, Greene, Jersey, Macoupin, Madison, Monroe, Montgomery, Morgan, Pike, St. Clair, Randolph, Sangamon, Scott, Washington

Marion Region
Counties: Alexander, Clay, Crawford, Edwards, Effingham, Fayette, Franklin, Gallatin, Hamilton, Hardin, Jackson, Jasper, Jefferson, Johnson, Lawrence, Marion, Massac, Perry, Pope, Pulaski, Richland, Saline, Union, Wabash, Wayne, White, Williamson

Peoria Region
Counties: Adams, Brown, Bureau, Cass, Fulton, Hancock, Henderson, Henry, Knox, LaSalle, Logan, Marshall, Mason, McDonough, Menard, Mercer, Peoria, Putnam, Rock Island, Schuyler, Stark, Tazewell, Warren, Woodford

Rockford Region
Counties: Boone, Carroll, DeKalb, Jo Daviess, Lee, Ogle, Stephenson, Whiteside, Winnebago

West Chicago Region
Counties: DuPage, Grundy, Kane, Kankakee, Kendall, Lake, McHenry, Will