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 County, Maryland the Maryland State Senate. Member George C. Edwards (R), serves the 1st district in Maryland and Andrew A. Serafini (R), serves in the 2nd district. The county also is represented in Maryland General Assembly’s other primary division, the Maryland House of Delegates. Delegates who stand for Washington County include: Mike McKay (R) for District 1C, Neil Parrot (R) and William Wivell (R) for District 2A and Paul Cordermen (R) for District 2B. Washington County’s “leader” is known as the County Administrator. Currently, Rob Slocum serves as the Administrator. However, Washington County's County Commissioners exercise executive powers as they exist in