Mount Aso (阿蘇山 Aso-san?) is the largest active volcano in Japan, and is among the largest in the world. It stands in Aso Kujū National Park in Kumamoto Prefecture, on the island of Kyūshū. Its peak is 1592 m above sea level. Aso has one of the largest calderas in the world (25 km north-south and 18 km east-west). The caldera has a circumference of around 120 km (75 mi), although sources vary on the exact distance.