Ohio Revised Code Title XLIX. Public Utilities § 4903.11

No proceeding to reverse, vacate, or modify a final order of the public utilities commission is commenced unless the notice of appeal is filed within sixty days after the date of denial of the application for rehearing by operation of law or of the entry upon the journal of the commission of the order denying an application for rehearing or, if a rehearing is had, of the order made after such rehearing. An order denying an application for rehearing or an order made after a rehearing shall be served forthwith by regular mail upon all parties who have entered an appearance in the proceeding.