Mount Halla (Hallasan)

Rising 1,947 meters above sea level, it is the highest peak in South Korea and the massive shield volcano that formed the landmass beneath it. There is a local saying that “Jeju Island is Hallasan, and Hallasan is Jeju,” reflecting the reality that the island’s gentle slopes are actually the submerged flanks of this singular, massive volcano.

Designated as a UNESCO World Natural Heritage Site and a Biosphere Reserve, Hallasan is a geological treasure. Unlike the jagged granite peaks of the Korean mainland, Hallasan is a shield volcano formed by fluid basaltic lava, giving it broad, sweeping slopes that rise gradually from the sea before steepening sharply at the summit. This geological process also created the island’s unique topography, most notably the 368 oreum (parasitic cones) that dot the landscape. These small, grassy volcanic hills are scattered across the island’s flanks, creating a surreal, bumping landscape that is unique to Jeju.

At the very peak of the mountain lies the Baengnokdam, a crater lake that sits inside the volcano’s caldera. The name translates to “White Deer Lake,” derived from a folktale about mountain spirits (immortals) who would descend from the heavens to ride white deer and drink the pure waters of the crater. The lake’s appearance changes with the seasons and weather; it can be a crystal-clear mirror reflecting the sky or a mysterious, fog-shrouded void.

Ecologically, the mountain is famous for its vertical ecosystem. Because the mountain rises from a subtropical coastline to a sub-alpine summit, hiking up Hallasan is like walking from the subtropics to the tundra in a single day. The base is covered in broadleaf evergreen forests, which transition into temperate deciduous forests, and finally into sub-alpine coniferous forests near the peak, home to the endangered Korean fir (Abies koreana). In spring, the upper slopes are ablaze with royal azaleas, creating a stunning pink contrast against the dark volcanic rock.

For travelers, hiking Hallasan is a bucket-list achievement. There are two trails that lead to the summit: the Seongpanak Trail and the Gwaneumsa Trail. Seongpanak is longer (9.6 km) but has a gentler incline, winding mostly through lush forests. Gwaneumsa (8.7 km) is steeper and more rugged, offering dramatic views of the volcano’s cliffs and a suspension bridge over a ravine. Due to the mountain’s popularity and conservation efforts, hikers must reserve a climbing slot in advance and adhere to strict turnaround times to ensure they descend before sunset. Reaching the summit requires physical endurance, but standing on the edge of the Baengnokdam, looking out over the sea of clouds and the island below, is considered the quintessential Jeju experience.