This is the site of a 450-meter diameter, 11-hectare crater created by the volcanic activity of Mt. Hiyori. There are numerous openings and fumaroles along the valley, and the scenery of bubbling and boiling water inspired the name “Oni no sumu jigoku” (Where the demon’s live). As much as 10,000 tons of hot spring water of various types gush out of this area every day, which is supplied to hotels and inns in the hot spring resort. *A wheelchair-accessible ramp (with a maximum slope of 8%) is provided from the Park Service Center to the Jigokudani Observation Deck.