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
Washington (state) support. Washington, D. C.'s, own statehood movement in the 21st century includes a proposal to use the name "State of Washington, Douglass Commonwealth", which would conflict with the current state of Washington. Residents of Washington (known as "Washingtonians") and the Pacific Northwest simply refer to the state as "Washington," and the nation's capital "Washington, D. C.," "the other Washington," or simply "D. C.". Washington is the northwestern-most state of the contiguous United States. It borders Idaho to the east, bounded mostly by the meridian running north from the confluence of the Snake River and Clearwater River (about 116°57' west), except