Also known as Poplar Hill, this Georgian mansion was built between 1785 and 1787 for Robert Darnall, a great-grandson of the original grantee, Col. Henry Darnall. Henry Darnall received generous land grants from Lord Baltimore and by the time he died in 1711 owned vast tracts of land in five Maryland counties, including 27,000 acres in Prince George's County alone. This late-Georgian mansion has been home to several local jurists, a U.S. senator and an ambassador. The grounds contain a full suite of historic outbuildings, including a slave infirmary, dairy smokehouse and privy. There's also a family cemetery, an herb garden, a working horse farm and a carriage house with conveyances from the 19th and early 20th centuries.
The grounds are also open the second and fourth Sundays of every month from 1 to 4 p.m.