Harmony Hall is in the Broad Creek Historic District, the first historic district formed under Prince George's County (Maryland) preservation law. The house is an 18th-century Georgian country house that architecturally ranks as one of the great early plantation houses and an outstanding early colonial house of Maryland. The front of the house faces the Potomac River and remains much as it appeared in 1766, the estimated time of construction.
Archeological objects systematically recovered from sites within the park's boundaries and associated field records.
(National Capital Parks–East)