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
Fort Washington, Maryland Fort Washington, Maryland Fort Washington is an unincorporated area and census-designated place in Prince George's County, Maryland. It borders the capital of the United States of America, Washington, D.C., situated just south of the downtown district. As of the 2010 census it had a population of 23,717. It is a prosperous community with an African American majority population. The Fort Washington community is located west of Maryland Route 210, with some additional area to the east of the highway. The community is named for Fort Washington, which upon its completion in 1809 was the only defensive fort protecting Washington, D.C.