Gunung Leuser National Park is a national park covering 7,927 km² in northern Sumatra, Indonesia, straddling the border of North Sumatra and Aceh provinces. The national park, named after 3,381 m height of Mount Leuser, protects a wide range of ecosystems. An orangutan sanctuary of Bukit Lawang is located inside the park.

Geography
Gunung Leuser National Park is one of the two remaining habitat for Sumatran Orangutans (Pongo abelii).

Ecology
In November 1995 the Langkat Regency government proposed a road to connect an old enclave, known as Sapo Padang, inside the park. Sensing of economic prospects, 34 families who had been living in the enclave formed a local cooperation unit in March 1996 and subsequently made a proposal to develop an oil palm plantation in August 1997. The legal process did not stop the project that extensive logging and clearing, road-building and oil palm plantation continue operating inside the national park.