Ohio Rev. Code § 5511.10: Signs in area of part of national park system.

(A) Except as provided in division (B) of this section, signs that indicate the presence of an area that is part of the national park system and are erected on highways that are part of the state highway system shall display the arrowhead symbol of the national park service as described in 36 C.F.R. 11.1 next to the name of the area.

(B) All signs erected as of the effective date of this section that indicate the presence of an area that is part of the national park system but that do not display the arrowhead symbol of the national park service shall not be required to display the symbol. When the sign is replaced according to the standard procedures and schedule of replacement as established by the department of transportation, the new sign shall comply with division (A) of this section.