Jefferson County is located in the Shenandoah Valley in the Eastern Panhandle of West Virginia, and is the easternmost county of the U.S. state of West Virginia. As of the 2010 census the population was 53,498. Its county seat is Charles Town. The county was founded in 1801, and today is part of the Washington metropolitan area.

Front Royal is the only incorporated town in Warren County, Virginia, United States. The population was 14,440 at the 2010 census. It is the county seat of Warren County.

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.

Hampshire County is a county in the U.S. state of West Virginia. As of the 2010 census, the population was 23,964. Its county seat is Romney, West Virginia's oldest town (1762). The county was created by the Virginia General Assembly in 1754, from parts of Frederick and Augusta Counties (Virginia) and is the state's oldest county. The county lies in both West Virginia's Eastern Panhandle and Potomac Highlands regions. Hampshire County is part of the Winchester, VA-WV Metropolitan Statistical Area.