Frederick County, Maryland Frederick County, Maryland Frederick County is located in the northern part of the U.S. state of Maryland. As of the 2010 U.S. Census, the population was 240,336. The county seat is Frederick. Frederick County is included in the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area. Like other outlying sections of the Washington metropolitan area, Frederick County has experienced a rapid population increase in recent years. It borders the southern border of Pennsylvania and the northeastern border of Virginia. The county is home to Catoctin Mountain Park (encompassing the presidential retreat Camp David) and to the U.S. Army's Fort Detrick. It has also
Maryland in the American Revolution capital of the colonies when the Second Continental Congress met there during December 1776 to February 1777, after Philadelphia had been threatened with occupation by the British "Redcoats". Towards the end of the struggle, from November 26, 1783, to June 3, 1784, the state's capital Annapolis, briefly served as the capital of the fledgling confederation government (1781-1789) of the United States of America, and it was in the Old Senate Chamber of the Maryland State House on State Circle in Annapolis that General George Washington famously resigned his commission as commander in chief of the Continental Army on December 23,