Martinsburg is a city in and the county seat of Berkeley County, West Virginia, United States, in the tip of the state's Eastern Panhandle region in the lower Shenandoah Valley. Its population was 17,454 in the 2019 census estimate, making it the largest city in the Eastern Panhandle and the eighth-largest municipality in the state. Martinsburg is part of the Hagerstown-Martinsburg, MD-WV Metropolitan Statistical Area.
Martinsburg was established by an act of the Virginia General Assembly that was adopted in December 1778 during the American Revolutionary War. Founder Major General Adam Stephen named the gateway town to the Shenandoah Valley along Tuscarora Creek in honor of Colonel Thomas Bryan Martin, a nephew of Thomas Fairfax, 6th Lord Fairfax of Cameron.
Aspen Hall, a Georgian mansion, is the oldest house in the city. Part was built in 1745 by Edward Beeson, Sr. Aspen Hall and its wealthy residents had key roles in the agricultural, religious, transportation, and political history of the region. Significant events related to the French and Indian War; the Revolution, and the Civil War took place on the property. Three original buildings are still standing, including the rare blockhouse of Mendenhall's Fort.
The first United States post office in what is now West Virginia was established at Martinsburg in 1792.