Ohio Rev. Code Ann. § 5591.12

In the establishment or making of any change in the location of any highway as shown on the plan or required by the construction contract, or any relocation or vacation of the whole or any part of such highway by the board of county commissioners, the same proceeding shall be had by it as is provided for the establishment, change of location, relocation, widening, vacation, or establishing or re-establishing a grade for a highway as in the case of county roads within the jurisdiction of such board.