Initially the area was not called Prince George's County, the area along the Patuxent was part of Calvert County and the area along the Potomac part of Charles County. By 1695, the governor thought the population was sufficient to deserve the right of self-government and the General Assembly agreed. On St. George's Day, April 23, 1696, a new county was established, named for Prince George of Denmark, husband of the heir to the throne of England, Princess Anne. Extending from the Charles County line on the south all the way to the Pennsylvania border, the new county marked Maryland's western frontier and remained so until 1748. In 1791, portions of Prince George's County were ceded to form the new District of Columbia.
Anne Arundel, Calvert, Charles, Howard and Montgomery counties along with Fairfax County, Virginia, the City of Alexandria, Virginia and Washington, DC.