The trace of an explosion crater with a diameter of approximately 450m and an area of approximately 11ha, formed by the volcanic activity of Hiyoriyama. Along the valley, numerous hot spring vents and fumaroles exist, and the scenery of bubbling and boiling became the origin of "Hell where demons dwell." From here, as much as 10,000 tons of various types of hot springs gush out per day, and hot water is supplied to the hotels and Japanese inns of the hot spring town.

※ A wheelchair-accessible ramp (maximum gradient 8%) has been installed from the Park Service Center to the Jigokudani Observation Deck.