The Tri-State Tollway is a U.S. toll road maintained by the Illinois State Toll Highway Authority (ISTHA) in northeastern Illinois which is considered one of the most heavily traveled highways in the country (according to the IBTTA, the tollway is the nation's 4th busiest toll road). It is actually a combination of three different Interstates: Interstate 80 between Interstate 94 at Thornton and Interstate 294 near Hazel Crest

I-294, which is routed concurrently with I-80 to Hazel Crest, and then turns north to Deerfield

I-94 north from Deerfield to U.S. Route 41

The segment containing Interstate 294 is 53 miles (85 km) long; in total, the Tri-State Tollway is actually about 78 miles (126 km) long. Only the Ronald Reagan Memorial Tollway is longer. Despite its name, the Tri-State Tollway does not enter either Indiana or Wisconsin. On the Indiana side, the Tri-State Tollway ends three miles (5 km) away from the Indiana border and continues as the Kingery Expressway; however both the Kingery and the Indiana portion, which was later named the Borman Expressway, were known as the Tri-State Highway before the Tollway was completed. On the Wisconsin side, the toll road ends just before the border at U.S. Route 41 and Russell Road, although ISTHA maintenance continues to the state line.

en.wikipedia.org/wiki/Tri-State_Tollway