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 State House New York). From November 26, 1783 to August 13, 1784, Annapolis was the capital of the United States. The Congress of the Confederation met in the Maryland State House. Subsequently, Annapolis was a candidate to become the new permanent national capital before Washington, D.C. was built. It was in the Old Senate Chamber that Congress ratified the Treaty of Paris on January 14, 1784, formally ending the American Revolutionary War. The United States District Court for the District of Maryland met there for the first decade of its existence. In 1800, judge Samuel Chase tried a local postmaster for embezzlement