Mount Airy was a 17th century hunting lodge of the Lords Baltimore. Its 9200 acres were acquired in 1751 by the honorable Benedict Calvert, a member of the council and son of Charles, Fifth Lord Baltimore. Here, with George Washington present, Benedict's daughter "Nelly" married John Parke Custis on February 4, 1774; he was the son of Martha Washington. Their son, George Washington Parke Custis, was born here, later married Marry Lee Fitzhugh, and built "Arlington" on the Potomac.