Gunung Leuser National Park, in northern Sumatra, covers about 7,900 km² of rainforest and mountains. It is part of the wider Leuser Ecosystem, the last place on Earth where Sumatran orangutans, tigers, elephants and rhinos still live together in the wild. For visitors, it offers one of the best chances in the world to see the critically endangered Sumatran orangutan.
At a glance
| Best time | Year-round; drier from about May to September |
| Getting there | Bukit Lawang is about 3 to 4 hours by road from Medan |
| Time needed | 3 to 5 days |
| Big draws | Sumatran orangutans, jungle treks, river tubing |
| Good for | Active travellers, backpackers, primate lovers |
Sumatran orangutans
- Sumatran orangutans are rarer than Bornean orangutans, with slimmer builds, longer faces and paler, reddish hair. Around 14,000 remain. See our Sumatran orangutan profile.
- Around Bukit Lawang, a former rehabilitation centre released many orangutans into the forest; their descendants live wild but are used to people, so sightings on treks are very likely.
- A third orangutan species, the Tapanuli orangutan, was described in 2017 from the Batang Toru forest further south; it is not usually visited by tourists.
Trekking
- Treks range from a few hours to several days, sleeping in simple jungle camps by rivers.
- Trails are steep and muddy, and humidity is high.
- Many multi-day treks end by rafting back to Bukit Lawang on inflated inner tubes.
- Trekking inside the park requires a permit and a licensed guide.
Other wildlife
Thomas’s leaf monkeys, white-handed gibbons, siamangs, long-tailed macaques, hornbills, monitor lizards and, rarely, sun bears and elephants. Tigers and rhinos are present in remote parts of the ecosystem but are almost never seen.
Ketambe
In the heart of the park, Ketambe is quieter and more remote than Bukit Lawang, with a long-running research station and good chances of wild orangutans, gibbons and hornbills.
Responsible trekking
Some guides have been criticised for feeding orangutans to guarantee sightings, which spreads disease and makes orangutans aggressive.
- Choose licensed guides who follow the park’s rules: no feeding, no touching, and staying at least 10 metres away.
- Limit group sizes and time with orangutans.
- Do not trek if you are sick.
- Take all rubbish out of the forest.
When to go
Year-round. The drier months (roughly May to September) make trekking easier, though rain can fall at any time.
Getting there
Fly to Medan (Kualanamu International Airport), then drive 3 to 4 hours to Bukit Lawang. Ketambe is further, about 8 to 10 hours from Medan.
Frequently asked questions
How likely am I to see orangutans in Bukit Lawang? Very likely on a trek of a day or more.
Is Gunung Leuser suitable for beginners? Yes, with a shorter trek and a good guide. Multi-day treks require reasonable fitness.
What is the difference between Sumatran and Bornean orangutans? Sumatran orangutans are slimmer, with longer hair and faces, and more arboreal; they are also rarer.
Can I see tigers in Gunung Leuser? Tigers live in the Leuser Ecosystem, but sightings are extremely rare.
Related guides
- Borneo wildlife guide: where to see orangutans
- Tanjung Puting: orangutans by klotok
- Danum Valley rainforest guide
- Animal profiles: Sumatran orangutan, Sumatran rhinoceros, Tiger
Cover photo: Junaidi Hanafiah, CC BY-SA 4.0, via Wikimedia Commons