Mount Asama is an active complex volcano in central Honshū, the main island of Japan. The volcano is the most active on Honshū. The Japan Meteorological Agency classifies Mount Asama as rank A. It stands 2,568 metres (8,425 ft) above sea level on the border of Gunma and Nagano prefectures. It is included in 100 Famous Japanese Mountains.

Gunma Prefecture is a landlocked prefecture of Japan located in the Kantō region of Honshu. Gunma Prefecture has a population of 1,937,626 and has a geographic area of 6,362 km2. Gunma Prefecture borders Niigata Prefecture and Fukushima Prefecture to the north, Nagano Prefecture to the southwest, Saitama Prefecture to the south, and Tochigi Prefecture to the east.