Ohio Rev. Code § 709.44: Territory that may be merged.

The territory of one or more municipal corporations, whether or not adjacent to one another, may be merged with that of an adjacent municipal corporation, and the unincorporated area of a township may be merged with one or more municipal corporations, or one or more municipal corporations, whether or not adjacent to one another, may be merged with that of an adjacent unincorporated area of a township, in the manner provided in sections 709.43 to 709.48 of the Revised Code.