IL 78 highlighted in red | ||||
Route information | ||||
Maintained by IDOT | ||||
Length | 215.51 mi[1] (346.83 km) | |||
Existed | 1924[3]–present | |||
Major junctions | ||||
South end | ![]() ![]() ![]() | |||
North end | ![]() | |||
Location | ||||
Country | United States | |||
State | Illinois | |||
Counties | Morgan, Cass, Mason, Fulton, Knox, Peoria, Stark, Henry, Whiteside, Carroll, Jo Daviess | |||
Highway system | ||||
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Illinois Route 78 is a major north–south highway in western Illinois. It runs from Illinois Route 104 northwest of Jacksonville north to Highway 78 at the Wisconsin state line north of Warren. This is a distance of 215.51 miles (346.83 km).[1]