^Westbound trailblazer at the eastern end, the meeting of Illinois 78 in Kewanee, August 2017.
Illinois Route 81 runs west across the latitudinal midline of Henry County. Somehow, Henry County, the next county east of the Quad Cities, got a pair of state routes to run across the latitudinal midline and the longitudinal midline of the county without entering any other counties. Those two routes are Illinois Route 81 and Illinois Route 82, the latter of which runs north-south along the longitudinal midline. Illinois 81 starts about fifteen miles south of the Quad Cities and heads east through Cambridge to end in Kewanee.
Illinois 81's west end is near Lynn Center at US Route 150:
Illinois 81's west end is near Lynn Center at US Route 150:
Heading only a few miles east of its western beginning, Illinois 81 reaches an interchange with the north-south section of Interstate 74...
In Cambridge, Illinois 81 reaches Illinois 82, which joins from the south:
Exiting the east side of Cambridge, Illinois 81 splits with Illinois 82 to send it continuing northward:
In Kewanee, Illinois 81 ends at Illinois 78 just north of that route's split with US Route 34.
