The Battle of Matewan (also known as the Matewan massacre) was a shootout in the town of Matewan in Mingo County and the Pocahontas Coalfield mining district, in southern West Virginia. It occurred on May 19, 1920 between local coal miners and their allies and the Baldwin–Felts Detective Agency. The dead included two brothers of the detective agency's founder and Matewan's mayor Cabell Testerman, who supported the union.