Islands of Borneo and Sumatra.
Bornean orangutans live high in the tropical canopy of Borneo's forests, where they survive predominantly on fruit and sleep in nests constructed from branches. Females give birth only once every eight years, and it is this sluggish reproduction rate which makes orangutans so susceptible to population depletion. Orangutans are native to parts of Indonesia and Malaysia. They can be found on the islands of Borneo and Sumatra. Their natural habitat is in the rainforest areas of these islands. Unfortunately, deforestation in many of these areas have severely impacted the population of orangutans. Wild orangutans live only on the islands of Borneo and Sumatra. Their population on Sumatra is currently limited to the provinces of Aceh and North Sumatra. Most Sumatran orangutans (Pongo abelii) are found in Aceh. Orangutans also live in dry forests that cover the foothills of mountains. But the apes do not extend far up mountainsides. They rarely live above 500 metres (1,640 feet) elevation on Borneo and above 1,000 metres (3,300 feet) on Sumatra. Two islands in southeast Asia  Borneo and Sumatra  are the only places where orangutans live. Each island has its own species of orangutan, that's named after the island. So Sumatran orangutans live on Sumatra and Bornean orangutans live on Borneo. Sumatra is part of Indonesia, while Borneo is divided among three countries. Bornean orangutans live in both Indonesia and Malaysia. Overall, Indonesia is where about 80 percent of the world's wild orangutans remain. Bornean orangutans are divided into three subspecies, each occupying different parts of the Island. All the subspecies are found in Indonesia and two also live in the Malaysian portion of Borneo. The map of Borneo, below, shows colored in orange–brown, where orangutans lived as of 2004. Where orangutans live on Borneo is colored in orange–brown.
http://www.bbc.co.uk/nature/life/Bornean_Orangutan http://wanttoknowit.com/where-do-orangutans-live/ http://www.orangutanrepublik.org/faqs-mainmenu-28/20-about-orangutans/60-where-do-wild-orangutans-live http://www.currentresults.com/Endangered-Animals/where-do-orangutans-live.php http://www.currentresults.com/Endangered-Animals/where-do-orangutans-live.php http://www.currentresults.com/Endangered-Animals/where-do-orangutans-live.php
where orangutans live