^Westbound signage at Old Chicago Road, northwest of Bourbonnais, September 2024.
Illinois Route 102 runs in Will and Kankakee Counties along the north side of the Kankakee River, on the opposite bank from Illinois Route 113. It connects the Kankakee area to Wilmington, Illinois, and it's used to access a lot of the use areas in Kankakee River State Park.
Illinois 102 has its northwestern inception at Illinois 53, in Wilmington:
Illinois 102 intersects no other state-maintained highways between its northwestern terminus and its southeastern terminus, which is at US Route 45 and US Route 52 (duplexed) in Bourbonnais (a suburb of Kankakee):