605 ILCS 5/6-321
All township and district roads heretofore or hereafter laid out upon district or county lines shall be divided, allotted and kept in repair in the manner as hereinbefore directed. Any township or district road that is or shall be laid out on any county or district line, and in case a railroad right-of-way or a stream of water forms the boundary line of such district or county, or crowds the public road off from such district or county, then the road alongside such railroad right-of-way or stream of water, shall be held to be a road on a county or district line, although owing to the topography of the ground along such county or district line, or at the crossing of any stream of water, the proper authorities in laying out such road may have located a portion of the same to one side of such county or district line or railroad right-of-way, or stream of water, and the expenses of keeping in repair such road shall be assessed by each district or county interested.
605 ILCS 5/6-321