Informal term describing regions bordering on three US states
Tri-state area[1][2] is an informal term in the United States which can refer to any of multiple areas that lie across three states. When referring to populated areas, the term implies a shared economy or culture among the area's residents, typically concentrated around a central metropolis.
Tri-state areas may or may not include a state boundary tripoint.
Tri-state areas by region
The following is not an exhaustive list. "Tri-state area" may refer to several additional places in locally understood contexts, such as a business name.
The Berkshires, a region usually considered to include only western Massachusetts and northwestern Connecticut; when the Taconic portion of New York is included, the area is sometimes described as the "tri-state" or "tri-corners" area.
The DMV, which includes the city of Washington (coterminous with the District of Columbia) as well as surrounding portions of Maryland and Virginia. Although the District of Columbia is not a state, the region is sometimes referred to as a "tri-state area." Furthermore, the Washington–Arlington–Alexandria metropolitan statistical area, as defined by the U.S. Census Bureau, includes Jefferson County, West Virginia, making the region a true tri-state area.