Mount Leuser National Park is one of the largest national parks in the world, containing over 950,000 hectares of virgin rainforest. The park is home to orangutans, gibbons, monkeys, elephants, tigers, and among the last of the Sumatran rhinoceros. There are research facilities for the study of primates, birds and insects, the Orangutans rehabilitation center at Bukit Lawang being the most popular with tourists. It is possible to raft Alas River from Ketambe to the Indian Ocean on a 4 - 5 day expedition. The journey takes us through exciting white-water rapids to the calmer, crocodile-infested waters of the lowlands. Basic accommodation is available at Ketambe.
Mount Leuser National Park is probably the wildest in Indonesia, located in Southeast Aceh, can be reached from either Kutacane, or Takengon. This magnificent national park has a wealth of flora and fauna. The Leuser Ecosystem is an outstanding wilderness in Aceh northern Sumatra. It is one of the richest expanses of tropical rain forest in Southeast Asia. More than 2.5 million hectares in size, it is the last place on earth where elephants, rhinos, tigers, clouded leopards, and orangutans are found within one area.