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
Maryland in the American Civil War and in particular whether such conditions formed part of a deliberate policy of "vindictive directives" from Washington, is a matter of some debate. The state capital Annapolis's western suburb of Parole became a camp where prisoners-of-war would await formal exchange in the early years of the war. Around 70,000 soldiers passed through Camp Parole until Lt. Gen. Ulysses S. Grant assumed command as General-in-Chief of the Union Army in 1864, and ended the system of prisoner exchanges. Those who voted for Maryland to remain in the Union did not at first contemplate the emancipation of Maryland's many slaves, or indeed