Ohio Revised Code Title LV. Roads Highways Bridges § 5555.81

When it is desired to construct, improve, or repair a road on or along the line between this state and an adjoining state, the board of county commissioners of any county of this state may join with the proper authorities of any adjoining state, or subdivision thereof, in such construction or improvement. Each party to such agreement shall pay such proportion of the costs of said improvement as is agreed upon by the parties thereto.