Which island is shared by Indonesia, Malaysia and Brunei?
Quick answer
Borneo is the island shared by Indonesia, Malaysia and Brunei. It’s the third-largest island in the world, after Greenland and New Guinea, and the only island divided among three countries. It’s famous for ancient rainforests, orangutans and Southeast Asia’s tallest peak outside New Guinea, Mount Kinabalu.
Key facts
- Area
- About 743,000 km²
- Rank
- Third-largest island in the world
- Countries
- Indonesia, Malaysia, Brunei
- Highest point
- Mount Kinabalu, 4,095 m
How Borneo is divided
| Country | Part of Borneo | Share of the island |
|---|---|---|
| Indonesia | Kalimantan | About 73% |
| Malaysia | Sabah and Sarawak | About 26% |
| Brunei | The whole country | About 1% |
Brunei, a small, oil-rich sultanate, is entirely on Borneo, split into two parts by Malaysian territory.
Rainforests and wildlife
Borneo’s rainforests are among the oldest in the world, around 130 million years old. They’re home to:
- Bornean orangutans, critically endangered great apes
- Proboscis monkeys, with long, drooping noses
- Pygmy elephants
- Rafflesia, flowers that can grow nearly 1 m wide
- Hornbills, clouded leopards and thousands of plant species
Under threat
Large areas of forest have been cleared for logging and oil palm plantations, and fires have destroyed more. Conservation groups and governments are working to protect remaining forests and wildlife corridors.
Mount Kinabalu
Mount Kinabalu in Sabah, Malaysia, rises to 4,095 m. It’s a UNESCO World Heritage Site, and thousands of climbers reach its granite summit each year, usually starting before dawn on the second day.
A new capital
Indonesia is building its new capital, Nusantara, in East Kalimantan on Borneo, to replace crowded, sinking Jakarta; see the world’s largest archipelago country.
Wallace’s line
Naturalist Alfred Russel Wallace explored Borneo in the 1850s. A famous boundary between Asian and Australian wildlife runs just east of the island; see who proposed natural selection alongside Darwin. For the world’s biggest island, see the largest island in the world.
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