Rosaryville State Park is a public recreation area with historical features located three miles southeast of Joint Base Andrews in Rosaryville, Prince George's County, Maryland. The state park includes the restored Mount Airy Mansion, which was formerly operated as an event facility, as well as hiking, biking and equestrian trails for day-use.

Benedict Swingate Calvert was a planter, politician and a Loyalist in Maryland during the American Revolution. He was the son of Charles Calvert, 5th Baron Baltimore, the third Proprietor Governor of Maryland (1699–1751). His mother's identity is not known, though one source speculates that she was Melusina von der Schulenburg, Countess of Walsingham. As he was illegitimate, he was not able to inherit his father's title or estates, which passed instead to his half brother Frederick Calvert, 6th Baron Baltimore (1731–1771). Benedict Calvert spent most of his life as a politician, judge and planter in Maryland, though Frederick, by contrast, never visited the colony. Calvert became wealthy through proprietarial patronage and became an important colonial official, but he would lose his offices and his political power, though not his land and wealth, during the American Revolution.