Hagerstown is a city in Washington County, Maryland, United States, and its county seat. The population was 43,527 at the 2020 census. Hagerstown ranks as Maryland's sixth-most populous incorporated city and is the most populous city in the Maryland Panhandle.

Hagerstown anchors the Hagerstown metropolitan area extending into West Virginia. It makes up the northwesternmost portion of the Washington–Baltimore combined statistical area in the heart of the Great Appalachian Valley. The population of the metropolitan area in 2020 was 293,844. Greater Hagerstown was the fastest-growing metropolitan area in the state of Maryland and among the fastest growing in the United States, as of 2009.

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 edgewise conglomerate and wavy laminae become distinctly visible, giving an appearance unique to the Cumberland Valley as seen in the architecture of St. John's Episcopal Church.

Despite its semi-rural Western Maryland setting, Hagerstown is a center of transit and commerce. Interstates 81 and 70, CSX, Norfolk Southern, and the Winchester and Western railroads, as well as Hagerstown Regional Airport form an extensive transportation network for the city. Hagerstown is also the chief commercial and industrial hub for a greater tri-state area that includes much of Western Maryland as well as significant portions of South Central Pennsylvania and the Martinsburg Panhandle Area. Hagerstown has often been referred to as, and is nicknamed, the Hub City.