Ohio Rev. Code § 707.22
When electors residing in two or more counties desire the organization of such territory into a municipal corporation, the petition shall be made to the board of county commissioners of the county in which the largest number of qualified voters of the proposed municipal corporation reside, and a statement to that effect shall be set forth in the petition. The transcript of the proceedings of the board, if required, and the other papers relating to the incorporation shall be recorded in the county in which the petition is filed in the manner provided by section 707.09 of the Revised Code. Within ten days after such recording the county recorder shall make a certified transcript of such record for each of the other counties in which any portion of the territory is situated, and shall forward such transcript to the recorders of such counties, who shall record them in the manner required for original papers.
In all other respects, the proceedings to establish such municipal corporation, or review the action of the board, shall be as provided in sections 707.01 to 707.14 of the Revised Code for villages and sections 707.29 and 707.30 of the Revised Code for cities.
R.C. §707.22