The Taisetsuzan volcano group lies at the northern end of the Taisetsu-Tokachi graben in central Hokkaido. It consists of a complex of stratovolcanoes and lava domes associated with a 2-km-wide caldera. The eight satellitic volcanoes are aligned along a ring fracture that is centered over the eastern rim of the caldera. Asahidake, the highest peak of the complex, was constructed 3 km SW of the center of the caldera. Other stratovolcanoes are located along a NE-SW line cutting through the caldera that trends toward the Tokachi volcano complex to the SW. In contrast to the Tokachi group, no historical eruptions are known, although the latest phreatic eruption took place sometime after 1739 CE. Fumarolic areas are located on Asahidake, where at one time sulfur was mined, and in the caldera.