Oxon Hill Manor is a neo-Georgian house of 49 rooms, located at Forest Heights, Prince George's County, Maryland. It was designed in 1928 for Sumner Welles (1892-1961) by the Washington architect, Jules Henri de Sibour (1872-1938). It was built in 1929, and consists of a two-story main block of Flemish bond brick and a northern wing. Also on the property are two outbuildings contemporary with the house; a five-car garage and attached manager's quarters and greenhouse, and a stable. There are also formal gardens on the grounds.

Jules Gabriel Henri de Sibour was a French architect who worked in Washington, DC.