Located outside on West Plaza (High Street) The National Park Service (a bureau of the Department of the Interior) designated the Ohio Statehouse a National Historic Landmark in 1978. This honors the Statehouse as a nationally significant historic place for possessing exceptional value or quality in illustrating or interpreting the heritage of the United States. National Historic Landmark OHIO STATE HOUSE HAS BEEN DESIGNATED A NATIONAL HISTORIC LANDMARK THIS SITE POSSESSES NATHINAL SIGNIFICANCE IN COMMEMORATING THE HISTORY OF THE UNITED STATES OF AMERICA 1978 HERTAGE CONSERVATION AND RECREATION SERVICE UNITED STATES DEPARTMENT OF THE INTERIOR