The Grange was designated a National Historic Landmark in December 1960. The private National Park Foundation purchased the house and property and transferred it to the National Park Service. Congress authorized the National Memorial on April 27, 1962, requiring that it be relocated and then the house restored to appear as Hamilton knew it in 1802–1804, which is considered its period of historic significance. It was at the time determined that the claustrophobic Convent Avenue setting was inappropriate and that the country house should be viewed as a freestanding building. However, the house was not relocated earlier because of overwhelming local opposition to options offered that required moving it out of the neighborhood. The Grange was administratively listed on the National Register of Historic Places on October 15, 1966.