Tanganyika, a lake of East Central Africa, stretching between the Congo Free State (W.) and German East Africa (E.); discovered by Speke and Burton in 1858; more carefully explored by Livingstone and Stanley in 1871; the overflow is carried off by the Lukuga into the Upper Congo; is girt round by lofty mountains; length 420 m., breadth from 15 to 80 m.