* Borneo:
* Found in the Indonesian provinces of Kalimantan and East Kalimantan, as well as the Malaysian states of Sabah and Sarawak.
* The Heart of Borneo, a significant conservation area, supports diverse orangutan populations.
* Sumatra:
* Occurs in the Indonesian provinces of Aceh, North Sumatra, West Sumatra, Riau, and Jambi.
* Key habitats include the Leuser Ecosystem, Batang Toru Forest, and Gunung Leuser National Park.
Orangutans prefer lowland and peat swamp forests, but can also be found in mountainous regions. They rely on mature forests with tall trees for nesting, foraging, and moving between areas.