Ohio Rev. Code Ann. § 709.47
(B) The municipal corporation with which merger is proposed succeeds to the following interests of each political subdivision proposed to be merged in:
(D) When a merger proposal includes the unincorporated area of a township, the board of county commissioners of the county in which the unincorporated area is located and the legislative authority of the municipal corporation with which merger is proposed shall negotiate an agreement requiring the county to continue providing within the unincorporated area for a determined period of time after the merger's effective date the county services it was providing within the unincorporated area on the day prior to the merger's effective date. During the negotiation process, each of the following shall occur:
(1) Before the merger's effective date, the board of county commissioners and the legislative authority of the municipal corporation shall each create a proposed transition plan that addresses, among other potential issues for agreement between the county and the municipal corporation, the following: