Ohio Rev. Code § 715.36: United States mail subways.

Any municipal corporation may, use, or by ordinance grant to any person, company, or corporation, for periods not exceeding twenty-five years, the use of its streets, avenues, alleys, lanes, and public places for the purpose of constructing, laying, maintaining, and operating subways and underground conduits, together with manholes and all other necessary appliances, for transmitting United States mail under such streets, avenues, alleys, lanes, and public places.