It travels from Interstate 74 in the small community of Goodfield to Illinois Route 17 in Toluca.

[1] Illinois 117 is a rural, two lane surface road for its entire length.

The main cities of service on Illinois 117 are Eureka and Roanoke.

Illinois 117 then overlaps Illinois Route 116 from four miles (6.4 km) west of Roanoke to Benson, a distance of about nine miles (14 km).

Northeast of Roanoke, Illinois 116/117 runs on top of an abandoned rail line until it turns north towards Toluca.