The park contains the Nakadake Crater, which is one of the few active volcanoes in the world accessible for direct viewing by the public when volcanic gas levels are low.
The caldera was formed by four massive volcanic eruptions that occurred between 90,000 and 300,000 years ago.
The park's grasslands are entirely man-made, kept free of trees through controlled burning, which preserves the habitat for rare mountain flora.
The Kuju mountains, located in the northern section of the park, include Kuju-san, the highest peak in Kyushu.
The caldera contains an entire city, Aso City, housing thousands of residents within the basin walls.
The region is home to the endangered Higo iris and various unique alpine plants that thrive in the nutrient-rich volcanic soil.
Aso-Kuju National Park spans a massive caldera, one of the largest in the world, with a circumference of approximately 120 kilometers. The park encompasses the active Nakadake volcano, part of the Aso Five Peaks chain. The landscape features extensive grasslands, known as Senomoto Kogen, maintained by controlled burning (noyaki) practiced for centuries. It spans both Kumamoto and Oita prefectures, connecting the Aso volcanic region with the Kuju mountain range. The area contains diverse geothermal features, including hot springs and active fumaroles. Visitors can traverse the Yamanami Highway for panoramic views of the caldera rim and highland moors.
The Daikanbo viewpoint on the northern rim for a full-scale panoramic view of the caldera and the Aso Five Peaks.
Check the official JMA volcanic activity status online before traveling, as gas levels frequently cause temporary zone closures.
Bring layers; temperatures on the caldera floor can be significantly different from the mountain ridges and highland areas.
Rent a vehicle to access remote hiking trailheads and scenic lookouts, as public transit is limited to main hubs.
Attempting to hike or enter restricted crater zones when the volcanic alert level is raised above 1.
Volcanic gas levels and ash fall can result in temporary, immediate closures of hiking trails and the crater area without prior notice.
Stay strictly on marked paths in volcanic zones to avoid toxic gases and hot ground; respect signage regarding volcanic alert levels.
