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
U-S-A! Show", where it may spontaneously and without apparent reason follow the show's standard cheer of "Jer-ry, Jer-ry!" and is also often delivered by Homer Simpson on "The Simpsons" as a celebration of almost anything, often accompanied by honking of his car's horn and flashing of its headlights. The chant is also used on "It's Always Sunny in Philadelphia" when the gang come up with a plan. U-S-A! "U-S-A!" is a chant of the United States of America's initials popular in expressing U.S. pride and supporting U.S. national sports teams. It is also used in other community events, such as at