Sundamgyegok Valley

Sundamgyegok Valley is a scenic valley along the Hantangang River in Cheorwon, Gangwon, set inside the broader UNESCO Global Geopark area near the inner Korean border. The valley features striking columnar-basalt cliff formations along the river — a defining geological signature of the Hantangang Geopark formed by lava-flow contact with cooling water — alongside clear-water river-bed sections, walking paths, viewing decks, and the famous Sundam swing-bridge crossing the river high above the water. The combination of dramatic basalt cliffs, the clear river water, and the surrounding mountain-and-forest landscape makes Sundamgyegok one of the Hantangang Geopark's most-cited landscape destinations. The valley is also a launching point for river-rafting programs that run in summer, with put-in and take-out points along the same walking corridor as the ridge-and-cliff footpath. Access: the site is reachable from Seoul in about 2 hours by car via the Gapyeong route; public transit is limited and typically requires a Seoul-to-Cheorwon bus plus a local transfer, so most visitors self-drive. Best in summer (June-August) for the strongest water flow and cooler atmosphere in the shaded corridor, and in late October for the autumn color layered over the basalt cliffs. Paired with broader Hantangang Geopark itineraries including Bidulginangpokpo Falls and Jaein Waterfall for a full valley-to-waterfall day.