Wikipedia
Kasaï-Oriental ( French for "East Kasai") was one of the eleven provinces of the Democratic Republic of the Congo between 1966 and 2015, when it was split into the new, smaller Kasai-Oriental province, the Lomami and the Sankuru provinces.
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.
Kasai-Oriental is one of the 26 provinces of the Democratic Republic of the Congo. Specified under Article 2 of the country's 2006 Constitution, the new province was finally created in 2015 from Tshilenge District and the independently administered city of Mbuji-Mayi, both part of the larger, pre-2015 Kasai-Oriental province. The new province's territory corresponds to the historic Sud-Kasaï province that existed the early period of post-colonial Democratic Republic of the Congo between 1963 and 1966.
The capital of the province is Mbuji-Mayi, formerly Bakwanga, on the Sankuru river.