Orange (river, Africa)

Orange (river, Africa), river in southern Africa, rising on the western slope of the Drakensberg range in Lesotho. It flows generally southwest through Lesotho and enters South Africa, where, turning northwest, it forms the boundary first between the provinces of Free State and Eastern Cape, and then between Free State and Northern Cape. The Orange continues on a western course through the northern part of the Northern Cape, finally forming the border between that province and Namibia. The Orange empties into the Atlantic Ocean at Alexander Bay. The Orange River is 2,100 km (1,300 mi) long; its chief tributary is the Vaal River.