Hagerstown /ˈheɪɡərztaʊn/ is a city in Washington County, Maryland, United States. It is the county seat of Washington County. The population of Hagerstown city proper at the 2010 census was 39,662, and the population of the Hagerstown-Martinsburg Metropolitan Area was 269,140. Hagerstown ranks as Maryland's sixth largest incorporated city.Hagerstown has a distinct topography, formed by stone ridges running from northeast to southwest through the center of town. Geography accordingly bounds its neighborhoods. These ridges consist of upper Stonehenge limestone. Many of the older buildings were built from this stone, which is easily quarried and dressed onsite. It whitens in weathering and the edgewisconglomerate and wavy laminae become distinctly visible, giving a handsome and uniquely “Cumberland Valley” appearance. Several of Hagerstown’s churches are constructed of Stonehenge limestone and its value and beauty as building rock may be seen particularly in St.