The name of Charles County is a tribute to Charles Calvert, third Lord Baltimore. Calvert lived in Maryland from 1661 until he returned to England in 1684. He was Proprietor of the Maryland colony from 1675 to 1689, when he lost his right to govern. From 1692 until Calvert's death in 1715, Maryland was governed as a royal colony.
The opening of the Potomac River Bridge (Harry W. Nice Bridge) in 1940 brought recognition to Charles County. The county seat is LaPlata.
