[2] Harmony Hall is a 2+1⁄2-story Georgian country house built of red brick during the eighteenth century.

After passing through other owners, the manor was purchased in about 1892 by Robert Stein, his brother Richard, and brother-in-law Joseph Adler.

They lost control of the manor house in 1929, selling it to Charles Collins, but continued to farm and operate a general store in the area.

Though the Park Service periodically sends in staff and enlists students to clean up the grounds, Harmony Hall competes with many other historic properties for attention and funding.

[8] Harmony Hall is also the name given to a community center building, on adjacent property, owned by the Maryland-National Capital Park and Planning Commission and used as their southern area headquarters office.