Kasaï-Oriental (East Kasai in English) is one of the ten provinces of the Democratic Republic of the Congo. It borders the provinces of Kasaï-Occidental to the west, Équateur to the northwest, Orientale to the northeast, Maniema to the east, and Katanga to the south. Kasaï-Oriental is one of the richest diamond producing regions in the world. The provincial capital is Mbuji-Mayi.