Mt. Kanmuri is a volcano located in the Sengokuhara area of Hakone at an elevation of 1,409 meters above sea level. It is one of the peaks that make up the central mountain chain of Hakone Volcano.
The northern summit is covered with trees and has no view. There are mountain trails leading up from Owakudani Station, Soun Station, and the summit of Mt. Komagatake. The course from Owakudani is sometimes closed when the concentration of volcanic gases is high.
About 2,900 years ago a phreatomagmatic explosion occurred on the northwest slope of Mt. Kamiyama, causing a major collapse and the magma reached the surface to form Mt. Kanmuri. The formation of this lava dome also generated pyroclastic flows, and some of the larger ones reached the base of the Nagao Pass on the outer rim of the Hakone mountains. The earth and sand that collapsed in this eruption dammed the Hayakawa River and created Lake Ashi and the highlands of Sengokuhara.