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.
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.