Idaho Code § 67-4117: Approval of markers, monuments and signs.

No marker, monument, nor sign referring to or memorializing any historic event shall be placed on or adjacent to any highway of the state of Idaho on land owned by the state of Idaho, or over which the state of Idaho has an easement, without the consent and approval of the department of the state having charge of the administration of said land, and the approval by the Idaho State Historical Society of the form and character of the marker, monument, or sign, and of the language used thereon.