Siberut National Park comprises 190,500.00 hectares of Siberut in the Mentawai Island of West Sumatera, Indonesia. The whole island including the national park is part of the World Network of Biosphere Reserves.

Siberut is the largest island of four islands in the Mentawai, which lies off the coast of west Sumatera. Siberut island lies south of the equator between the coordinates 98036' - 99003' East longitude and 1005' - 1045' South latitude. The distance between the island of Siberut and Sumatera island about 155 km acros the Mentawai Strait. Altitude 0 - 500 m above sea level, rainfall on average 2,900 - 3,700 mm/year.

Siberut is divided into five district : The North Siberut (Muara Sikabaluan), South Siberut (Muara Siberut), West Siberut (Simalegi), South-west of Siberut (Tailelu), Middle Siberut (Saibu Samukop).

The forest area of the park is still relatively natural, with abundant large trees with an average height or 60 metres. Some of 60 % of the forest area is covered by Dipterocarpaceae primary forest, mixed primary forest, swamp forest, coastal forest and mangrove forest.

Siberut National Park has four primate species which are found nowhere else in the world. They are  Bilou/Mentawai Gibbon (Hylobates klossii), Bokoi/Pagai pig-tailed Macaque (Macaca pagensis), Joja/Mentawai leaf Monkey (Presbytis potenziani siberu), and Simakobu/Pig-tailed leaf Monkey (Simias concolor siberu). In addition, there are four endemic species of aquirrel, 17 species of mammals, and 130 species of bird, four of them are endemic.

Siberut National Park is characterized by a wet equatorial climate, with minimum and maximum temperature of 220 and 310 C. The dry season is from February to June and the raining season is from Juli to Januari. Siberut is hilly with wide variation in elevation.

Many few visitors walk through the inlands parts of the park, the main attraction so far has been the culture of the Mentawai people who live in and around the park. The Mentawai people are among the many tribes of Indonesia who have preserved their very traditional way of life.  Most of the people still adhere to animistic beliefs. Their social activities are centred around the 'Uma", a communal longhouse which may be occupied by 30 to 80 people.

The Mentawaians believe that all living objects, men, plants, and animal are supposed to have spirit. The only specialist in the communitiy is the medicine man 'Kerei', responsible for communication with the spirits and the souls. In case of misfortune or illness, he is called in to restore harmony within the group or in relation with the spirits in the environment. An elaborate 'Taboo' system based on religious beliefs with respect to the environment  is a dominant characteristic of traditional life on Siberut.  Visit and stay in a Mentawaian village, trek to the jungle, learn about sago processinng and bark cloth processingn, and do other activities that will heighten your interest in and fascination with the natural philosophy of the Mentawaian.

Some good coral reefs can be found along the east, south to southeast part of Siberut and the surrounding small islands. Along the coast, continuous, white sand beach, magnificent lagoon, enficing mangroves and coral sea gardens all promise an exciting coastal adventure. Dolphins (Stenela longirostris) can be seen along the east coast. Other sea mammals such as Digong (Dugong dugong) occasionally can be sighted near the sea grass by the mangrove along with three protected species of sea turtles.

Masilok Beach on the southern part of Siberut can be reached within an hour by motorized boat. The island's resort, dominated by coconut grows, a lagoon with beautiful white sand beach, promising a very relaxing environment. The west coast breaks from Siberut island, connected only by sea garden and mangrove that lie side by side, making it a unique experience for diving. Accomodation and fresh clean water are available. Another activity is oaring with traditional sampan through the mangrove, zigzaging past the enormous and thick prop roots. Enjoy the scenery and bring back pictures to show off to friends.

Declared by Minister of Forestry No. 407/Kpts-IV/1993. October 8, 1993.