Calvert County is a county located in the U.S. state of Maryland. It occupies the Calvert Peninsula which is bordered on the east by the Chesapeake Bay and on the west by the Patuxent River. Calvert County is part of the Southern Maryland region. Calvert County's residents are among the highest median household-income in the United States.
As of 2010, the population was 88,737. Its county seat is the town of Prince Frederick, Maryland. The county's name is derived from the family name of the Barons of Baltimore, the proprietors of the English Colony of Maryland.
Calvert County is one of the several Maryland counties that make up part of the Washington Metropolitan Area or the Baltimore-Washington Metropolitan Area.