Like a peninsula the Mahle Mountains reach into the Tanganyika Lake and form a sanctuary of 1613km². The mountains are a product of the East African Rift Valley and are accessible by water or air only.Next to a direct domestic flight to the park it is also possible to travel with the passenger liner M.V. Liemba, a former German steamboat  from the first world war, which however needs a lot of patience and adventuresomeness as it is rarley adhered to the timetable.

An evergreen rain forest, which in the west turns into a moist-tropical mountain forest with a solid stock of bamboo, starts on the shore of Lake Tanganyika. Approximately 1000 chimpanzees live in the Mahale Mountains and plentiful big game lives in the drier east side of the park. The primates population rose strongly since the opening of the game reserve because the natives liked to hunt the chimps for their meat. Japanese scientists are researching the apes since 1961 and helped with their studies in this isolated area to found the national park and to give tourists an understanding of chimpanzees.