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
Capital Beltway station trains (the future MARC Penn Line) began stopping at Capital Beltway; the nearby Lanham and Landover stations were closed. Amtrak and Conrail abandoned Capital Beltway on October 30, 1983, in favor of nearby New Carrollton, which had been a Washington Metro stop since 1978. Capital Beltway station Capital Beltway was a railway station in Lanham, Maryland. It was built in 1970 by the Penn Central Transportation Company in partnership with the state of Maryland, the United States Department of Transportation (DOT), and Prince George's County. The station was located on the Northeast Corridor approximately north of Union Station in Washington,