IL-04

Counties

Boone, Bureau, Carroll, Cook, Dekalb, Du Page, Grundy, Henderson, Henry, Iroquois, Jo Daviess, Kane, Kankakee, Kendall, Knox, Lake, Lasalle, Lee, Livingston, Marshall, McHenry, Mercer, Ogle, Peoria, Putnam, Rock Island, Stark, Stephenson, Tazewell, Warren, Whiteside, Will, Winnebago, Woodford, Warren, Whiteside, Woodford