The Black Volta or Mouhoun is a river that flows through Burkina Faso flowing about 1,352 km (840 mi) to the White Volta in Dagbon, Ghana. The source of the Black Volta is in the Cascades Region of Burkina Faso, close to Mount Tenakourou, the highest point of the country. Further downstream it forms part of the border between Ghana and Côte d'Ivoire and Burkina Faso. Within Ghana, it forms the border between the Savannah Region and the Bono Region. The Bui Dam is built on the river in Ghana. The river bisects Bui National Park in Ghana.