Washington County is a county located in the western part of the US state of Maryland, bordering southern Pennsylvania to the north, northern Virginia to the south, and the Eastern Panhandle of West Virginia to the south and west. As of the 2010 Census, its population is 147,430. Washington County was the first county in the United States to be named for the Revolutionary War general (and later President) George Washington. Its county seat is Hagerstown.
Washington County is one of three counties in the Hagerstown-Martinsburg, MD-WV Metropolitan Statistical Area. Washington county has experienced a population boom, and is one of the fastest growing counties in the country, due to an influx of people from the Washington-Baltimore metropolitan areas.