Ohio Rev. Code § 5543.04
The county engineer, under the direction and supervision of the director of transportation, shall name and number all the public roads of his county, other than intercounty and state highways and shall number all the bridges and culverts on such roads. All such roads shall be divided into sections where they are of sufficient length to warrant it. Such sections shall not exceed three miles in length and shall be numbered consecutively. This section shall extend to all roads on the north and east lines of each county. A map of such roads shall be made by the engineer, which shall show and identify by number, location, and length each such road and section thereof and all bridges and culverts. Such map shall show the location of public recreational trails preserved by the board of county commissioners under section 5553.044 of the Revised Code, municipal corporations, schoolhouses, churches, lakes, and rivers, and shall be made in township units.
As rapidly as the roads, bridges, and culverts of each township are located and numbered, the engineer shall enter in a book in his office, to be kept for that purpose, a description or identification thereof. A copy of such map shall be submitted to the director together with a report showing plainly and definitely the exact location of such numbered roads and sections thereof, bridges, and culverts, and such other and further information as the director requires. All the duties required by this section shall be performed in accordance with the instructions of the director, who shall prescribe such forms and issue such instructions as he deems proper. Upon the approval by the director of each map and report, copies shall be filed by the engineer in his office and in the office of the board of county commissioners, and a copy of the map of each township shall be filed with the board of township trustees of such township. The road names, numbers, and section designations, and the bridge and culvert numbers shall be the official terms by which they are known. When a new road is established it shall be assigned a name and number by the engineer and if necessary divided into sections, or it may be added to an existing road, and the engineer shall note such new road, together with its official designation, on the copy of the map on file in his office and report it to the director and board of county commissioners.
R.C. §5543.04