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 George Washington was impressed with the Maryland regulars (the "Maryland Line") who fought in the Continental Army and, according to one tradition, this led him to bestow the name "Old Line State" on Maryland. Today, "the Old Line State" is one of Maryland's two official nicknames. The state also filled other roles during the war. For instance, the Continental Congress met briefly in Baltimore from December 20, 1776, through March 4, 1777. Baltimore served as the temporary capital of the colonies when the Second Continental Congress met there during December 1776 to February 1777, (when Philadelphia was occupied by the