Riversdale
- Also Known As: Calvert Mansion
- Address: 4811 Riverdale Rd
- Vicinity: Between 18th St and Taylor St
Riversdale's architectural significance derives from its role as one of the best late Georgian, five-part houses in Maryland. The Federal interior is of such high quality as to support the local tradition that attributes the design to William Thornton, architect of the Capitol. However, the available information on Thornton does not support the tradition. The historical significance of Riversdale rests with its builder, Henri Joseph the Baron de Stier, and his son-in-law George Calvert, who inherited the property. In 1794 de Stier immigrated to the United States from Belgium, which the French army had occupied. He lived in Anne Arundel County and in the Brice House in Annapolis immediately before building Riversdale, which he modeled after one of his European house. In 1799, de Stier's daughter married George Calvert, a descendant of the Lords Baltimore. Four years later, de Stier decided to return to Europe, leaving his Prince George's County residence in charge of his daughter and son-in-law. Charles Benedict Calvert succeeded his father as master of Riversdale. He devoted his life to agriculture through his supervision of this 2000-acre farm and through county, state, and national agricultural societies. His efforts through the United States Agricultural Society were responsible for the creation of the Department of Agriculture in 1853. Henry Clay often visited Calvert at Riversdale, staying in the northeast bedroom. Tradition maintains that he wrote a draft for the Compromise of 1850 while in that room. - Maryland Historical Trust