There is no organization called the “Royall House Association” in Medford. The historic site is the Royall House and Slave Quarters, a National Historic Landmark located at:
15 George Street, Medford, MA 02155
The property is operated by the Royall House Association (a nonprofit), but the association’s mailing address differs from the museum site. For visit hours, tour schedules, and research appointments, check the official website: royallhouse.org.