Ohio Rev. Code § 301.02
Previous to the presentation of a petition to the general assembly praying that a new county be erected, or for the location or relocation of a county seat, notice of the intention to present such petition shall be given, at least thirty days before the ensuing session of the general assembly, by advertisement in a newspaper of general circulation in each county from which such new county is intended to be taken. If no newspaper is of general circulation within the county, notice shall be given by advertisement affixed to the door of the house where courts are held for such county, for such period of thirty days. The notice shall set forth the boundary lines of the new county, or the place where it is proposed to locate such county seat.
R.C. § 301.02