The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States. However, the Bureau of Labor Statistics classifies the state as a part of the Mid-Atlantic region. The northern panhandle extends adjacent to Pennsylvania and Ohio, with the West Virginia cities of Wheeling and Weirton just across the border from the Pittsburgh metropolitan area, while Bluefield is less than 70 miles (110 km) from North Carolina. Huntington in the southwest is close to the states of Ohio and Kentucky, while Martinsburg and Harpers Ferry in the Eastern Panhandle region are considered part of the Washington metropolitan area, in between the states of Maryland and Virginia. The unique position of West Virginia means that it is often included in several U. S. geographical regions, including the Mid-Atlantic, the Upland South, and the Southeastern United States. It is the only state that is entirely within the area served by the Appalachian Regional Commission; the area is commonly defined as "Appalachia".