Geomunoreum

Jeju has more than 360 oreum, its small volcanic cones, but only one is part of the UNESCO World Natural Heritage site: Geomunoreum. Lava from this volcano flowed northeast all the way to the coast, creating some 20 lava tubes, including Manjanggul and Gimnyeonggul. Its dense forest looks dark from afar, hence the old name "Black Oreum." Today a limited number of visitors walk it each day, by reservation and with a guide.

Where the lava tubes begin

Geomunoreum rises from the hills of Seonheul-ri in Jocheon-eup, around 400 m above sea level, with a summit at 456.6 m. Its horseshoe-shaped crater opens to the northeast and holds a smaller peak inside it. Lava pouring out of the crater followed the slope to the sea and formed the Geomunoreum Lava Tube System. One branch runs almost straight for about 13 km to Dangcheomul Cave, threading Bengdwigul, Manjanggul and Gimnyeonggul along the way. The oreum became a Natural Monument in 2005, and in 2007 it was inscribed on the World Heritage List as part of "Jeju Volcanic Island and Lava Tubes."

The cone is estimated to have formed some 200,000 to 300,000 years ago, and about 20 lava tubes lie around it. Its early name was Bangha Oreum; the current one is thought to come from the Korean word for "black," after its unusually dark soil and forest. Several oreum on Jeju have similar names, so this one is often called Seonheul-ri Geomunoreum to tell them apart.

What to see

• The crater forest: Cedar and pine stands mix with evergreen and deciduous woodland, and damp hollows keep the air cool.
• A lava gorge: Where a lava-tube roof collapsed, a trench 80–150 m wide and 15–30 m deep remains, described as the longest lava gorge on Jeju.
• Japanese military remains: Tunnels and supply roads dug by the Japanese army at the end of the Pacific War are still visible.
• Summit views: From the ridge, row after row of oreum spreads across eastern Jeju.

Choosing a route

The Taegeuk Trail has three options:

• Summit course: 2.1 km, about 1 hour
• Crater course: 5.0 km, about 2.5 hours
• Ridge course (full loop): 6.7 km, about 3.5 hours

The 6 km Lava Trail, which follows the path of the lava flow, is normally closed and opens only during the annual Geomunoreum trekking event in summer; in 2026 it ran from 13 to 17 August.

During the trekking event entry is free and no booking is needed, but every visitor must complete a safety briefing at the visitor centre and collect a pass. A free shuttle runs every 30 minutes from the end of the Lava Trail back to the Heritage Center.

Nearby

• Jeju World Natural Heritage Center: The starting point, with exhibits that explain Jeju's volcanoes and lava tubes before you set off.
• Manjanggul: A lava tube created by Geomunoreum's flows and open to the public, the underground half of the same story.

Tripto tips

• Booking required: Unlike other oreum, entry needs an advance reservation. Groups set off every 30 minutes between 09:00 and 13:00.
• Closed: Tuesdays and Seollal and Chuseok days; access is suspended in bad weather.
• Fees: Listed at KRW 2,000 for adults and KRW 1,000 for teenagers and children.
• Meeting point: Jeju World Natural Heritage Center (569-36 Seongyo-ro, Jocheon-eup), with parking.
• Preparation: Forest paths get slippery after rain. Wear good walking shoes, carry water and pick a course that fits your schedule.