Ohio Rev. Code § 6133.02: Hearing - filing petition.

(A) When an improvement is proposed to be located in or benefits or damages land in two or more counties, the proceeding shall be conducted by a joint board of county commissioners consisting of the members of the boards of county commissioners of the several counties in which land may be benefited or damaged by the proposed improvement.

(B) The petition for a joint county drainage improvement shall be filed with the clerk of the board of county commissioners of the lead county.