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
Xfinity Center (College Park, Maryland) in the state of Maryland, it is the second-largest arena in the Washington, D.C. metropolitan area by seating capacity, just behind Capital One Arena in Washington, D.C., which has an official seating capacity of roughly 500 more than Xfinity Center. The facility is also used for concerts, graduation ceremonies including those for the University of Maryland, state high school basketball tournaments, and other special events. Concert seating capacity is nearly 19,000. In addition to the main basketball court, Xfinity Center also features a 1,500-seat gymnasium for volleyball, gymnastics, and wrestling; a 7,000-square-foot academic support center for student-athletes; Heritage Hall, a