阿蘇山
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 Kyushu. Its peak is above sea level. Mount Aso has a fairly large caldera (25 kilometers (16 miles) north-south and 18 km (11 mi) east-west) with a circumference of around , although sources vary on the exact distance.