Mount Ontake is a 3,067-meter-high active volcano in central Japan and is known as the country’s second-highest independent peak after Mount Fuji. Surrounded by magnificent mountain scenery, the area attracts hikers, mountaineers, nature lovers, and winter sports enthusiasts throughout the year.
Mount Ontake is also recognized as one of Japan’s 100 Famous Mountains, the New 100 Famous Mountains of Japan, and the 100 Famous Mountains of Flowers. Its appeal lies not only in its spectacular natural environment, but also in its long history as a sacred mountain.
Mount Ontake has an unusual landscape, with a broad, roughly trapezoidal summit area extending about 3.5 kilometers from north to south. Its vast foothills spread across Kiso Town and Otaki Village in Nagano Prefecture, as well as Gero City and Takayama City in Gifu Prefecture.
Five crater lakes are scattered around the summit area. They are known as Ichinō-ike, Nino-ike, Sanno-ike, Yono-ike, and Gono-ike, meaning the First through Fifth Ponds.
Among them, Nino-ike and Sanno-ike are especially famous for their striking emerald-colored water.
Located at an elevation of approximately 3,050 meters, Nino-ike is known as the highest-elevation lake in Japan. Sanno-ike is the largest crater lake on Mount Ontake, and its emerald-green surface has long been regarded as sacred by worshippers of the mountain.
For centuries, Mount Ontake has been revered as a sacred mountain. The mountain became an important center of Japanese mountain worship, a tradition in which mountains are regarded as sacred spaces inhabited by divine or spiritual forces.
Its popular religious following grew particularly strongly during the Edo period, when Mount Ontake became a destination for ordinary people as well as religious practitioners. Its tradition of popular pilgrimage is often compared with the widespread faith surrounding Mount Fuji.
At Kengamine, the highest point of Mount Ontake, stands the inner shrine of Ontake Shrine. The mountain was also known as a place of ascetic training for shugendō practitioners during the medieval period, when religious practitioners undertook rigorous training in the mountains.
Ontake Shrine has worship sites on both the Nagano and Gifu sides of the mountain. On the Nagano side, the Otakiguchi and Kurosawaguchi routes have their own shrine facilities.
The Okusha, or inner shrine, of the Kiso Ontake Shrine Otakiguchi is located at the summit of Otaki, while the inner shrine associated with Kurosawaguchi stands at Kengamine.
The principal deities enshrined at Ontake Shrine include Kunitokotachi-no-Mikoto, Ōnamuchi-no-Mikoto, and Sukunahikona-no-Mikoto. These deities have been worshipped as important figures within the mountain’s spiritual traditions, attracting pilgrims and worshippers from throughout Japan.
The Mount Ontake area supports a diverse ecosystem ranging from alpine environments near the summit to forests in the lower mountain regions.
During the Paleolithic period, approximately 30,000 years ago, large-antlered deer are believed to have inhabited the region. Kaida Highlands on the eastern side of the mountain was used as a hunting ground.
Today, birds such as spotted nutcrackers, rock ptarmigans, and peacock butterflies can be found in the alpine zone. The rock ptarmigan is designated as a Special Natural Monument of Japan and is classified as Critically Endangered IA by Japan’s Ministry of the Environment.
Other animals living in the mountain region include weasels, wild boar, raccoon dogs, Japanese black bears, Japanese macaques, and Japanese foxes. A wide variety of birds can also be observed, including bramblings, Japanese grosbeaks, pheasants, Eurasian treecreepers, coal tits, and broad-billed rollers.
The Breeding Ground of Broad-billed Rollers in Mitake, Kiso Town is designated as a Natural Monument of Japan.
The alpine plants of Mount Ontake were highly valued as “sacred herbs” during the late Edo period. The delicate komakusa, or Dicentra peregrina, was particularly prized for medicinal use, and excessive collection caused many natural populations to disappear.
Conservation and restoration efforts are now being carried out to protect these valuable alpine plants.
Near the summit, visitors can encounter alpine species such as blue mountain heather, Iwaume, mountain ash, crowberry, dwarf pine, alpine anemone, and Erman’s birch. In the subalpine zone, forests include Maries’ fir, Tsuga diversifolia, Veitch’s silver fir, Erman’s birch, spruce, and mountain ash.
The lower mountain forests contain deciduous broad-leaved trees such as Japanese beech, maples, chestnut, white birch, and mizunara oak, along with natural forests of Japanese horse chestnut, hinoki cypress, and other species.
Kiso hinoki cypress is particularly famous and is traditionally regarded as one of Japan’s three great forest resources.
Mount Ontake has also given its name to several species discovered in the region. Ontake-kuro-yotō, a moth belonging to the owlet moth family, is found in the alpine zone of Mount Ontake.
Another example is Ontake-bushi, a species of monkshood in the genus Aconitum. It was discovered on Mount Ontake and takes its Japanese name from the mountain. The plant is considered threatened and is classified as Critically Endangered IA by Japan’s Ministry of the Environment.
Mount Ontake has a network of climbing routes approaching the mountain from several directions, offering different experiences depending on the route and season.
The Otakiguchi Trail is particularly well known. It begins at Tanohara, at an elevation of 2,160 meters, the highest point accessible by road, and provides one of the shortest approaches to Kengamine.
The route offers expansive views between the trailhead and Otaki Summit, making it popular with a wide range of hikers and mountaineers.
Because Mount Ontake is an active volcano, visitors must take volcanic safety seriously when planning a climb.
Nagano and Gifu prefectures require climbers to submit mountain climbing notifications or plans in accordance with local regulations. Evacuation shelters have also been installed near the summit to provide protection in the event of volcanic activity.
Following the 2014 eruption, Mount Ontake has been subject to enhanced monitoring and observation. Anyone planning to climb should check the latest volcanic information, trail conditions, access restrictions, and safety guidance before setting out.
Mount Ontake is the 14th-highest mountain in Japan and the country’s second-highest volcano after Mount Fuji.
The main summit, Kengamine, is surrounded by peaks including Marishitensan at 2,959.2 meters, Tsukigodake at 2,858.9 meters, and Mayodake at 2,867 meters. Together, these peaks form the mountain’s distinctive broad, plateau-like profile.
Tsukigodake at the northern end is a relatively young stratovolcano. Because of its beautiful conical shape, it is also known as Hiyoriwa Fuji. On the Nagano side, volcanic features such as Mikasa-yama at 2,256 meters and Ko-Mikasa-yama at 2,029 meters add further variety to the landscape.
Mount Ontake lies at the western edge of the volcanic belt of eastern Japan. Its geological foundation consists largely of Paleozoic formations and Mesozoic Nohi rhyolites.
Volcanic activity produced stratovolcanic formations composed of materials including andesite and olivine-bearing volcanic rocks, with lava flows extending in several directions.
One particularly impressive example is the sixth Marishitensan lava flow on the western side of the mountain, which extends for approximately 17 kilometers.
Following a phreatic eruption in 1979, Mount Ontake has experienced intermittent small-scale fumarolic activity. Monitoring and observation systems continue to operate as part of volcanic disaster prevention measures.
The volcanic activity is a reminder of the immense natural forces that shaped the mountain, while the forests, alpine plants, lakes, and wildlife demonstrate how diverse ecosystems have developed around this dynamic landscape.
The volcanic geology of Mount Ontake is characterized mainly by andesite and dacite, together with lava flows and pyroclastic deposits.
The older Ontake volcanic complex is believed to have reached elevations of approximately 3,200 to 3,400 meters and was active from around 780,000 to 390,000 years ago.
Later, between approximately 100,000 and 20,000 years ago, the younger Ontake volcano developed, eventually forming the peaks and volcanic landscape seen today, including Kengamine and Marishitensan.
Of particular geological interest are four magmatic eruptions and more than ten phreatic eruptions during the past 10,000 years. Evidence of these eruptions can still be observed in the mountain’s terrain.
One of Mount Ontake’s most distinctive features is the group of five crater lakes near the summit. Known as Ichinō-ike through Gono-ike, these lakes were formed within the volcanic landscape.
Nino-ike and Sanno-ike are particularly notable for their beautiful emerald-colored water. Nino-ike is known as the highest-elevation lake in Japan, while Sanno-ike is the largest crater lake on Mount Ontake.
The water of Sanno-ike has long been regarded as sacred. Worshippers visiting Mount Ontake have traditionally revered it as “Goshinsui,” or sacred water.
Yono-ike is also notable for its high-altitude wetland environment, where alpine plants grow in a fragile and valuable ecosystem.
The area around Mount Ontake is known for its many waterfalls. Steep terrain, large differences in elevation, extensive forests, and abundant rainfall combine to create ideal conditions for waterfalls and mountain streams.
Among the waterfalls that can be visited relatively easily are Hyakuma-no-taki along the walking trail of the Aburaki Ridge near Kurosawaguchi, Onojima Falls in Kaida Highlands, and Taki Falls and Kiyotaki Falls near Otakiguchi.
Near Nigorigo Onsen, visitors can also find Sennin Falls and Hino Falls. Neo Falls is particularly famous and is included among Japan’s 100 Notable Waterfalls.
Shintaki and Kiyotaki are especially associated with the religious traditions of Ontakekyō, a faith centered on Mount Ontake. Shintaki includes a cave that has traditionally been used for ascetic practices such as fasting and takigyō, a form of purification involving standing beneath a waterfall.
In winter, Shintaki and Kiyotaki can freeze into spectacular columns of ice, creating a striking seasonal attraction.
Around the Reijinba area at the fourth station of the Kurosawaguchi route, visitors can also encounter waterfalls including Hinode Falls, Meiei Falls, Ōharai Falls, and Matsuo Falls. These places reflect the close connection between the natural environment and spiritual traditions of Mount Ontake.
Mount Ontake has long been regarded as one of Japan’s sacred mountains and is sometimes counted among the country’s Three Sacred Mountains.
Like Mount Fuji, it attracted widespread popular devotion. During the Edo period, the religious tradition known as Ontakekyō spread throughout Japan, encouraging ordinary people to undertake pilgrimages to the mountain.
During the Kamakura period, Mount Ontake was already known as a place of ascetic training for religious practitioners. By the middle of the Muromachi period, pilgrims were undertaking demanding journeys to the summit as part of their religious practice.
During the Edo period, the practitioner Kakumei Gyōja helped popularize a less demanding form of pilgrimage to Mount Ontake. As a result, the mountain became accessible to a broader range of ordinary worshippers.
Numerous sacred sites and places of religious practice can still be found throughout the mountain. The many Reijin monuments, stone monuments dedicated to revered religious figures, are an important part of the cultural landscape and offer visitors a glimpse into the mountain’s long history of faith.
From the modern period onward, Mount Ontake gradually developed as both a pilgrimage destination and a tourist attraction.
The first mountain hut began operating in 1868, and the traditional prohibition against women entering the mountain was lifted in 1872. These changes contributed to an increase in ordinary visitors and climbers.
Later, the opening of the Ontake Ropeway and the development of ski resorts helped establish the area as a destination that can be enjoyed throughout the year.
The foothills of Mount Ontake, particularly around Kiso Town and Otaki Village, are dotted with places where visitors can experience the area’s natural beauty throughout the seasons.
Hot spring destinations such as Nigorigo Onsen, Shintaki Onsen, and Kaida Highlands Onsen offer opportunities to relax in natural hot spring waters while enjoying the surrounding mountain scenery.
In winter, the region becomes a popular destination for skiing and other snow activities, with facilities including the Ontake Ropeway area and Ontake ski resorts.
During the warmer months, visitors can enjoy mountaineering, hiking, trekking, and camping. The combination of high mountain scenery, forests, waterfalls, volcanic landscapes, and centuries-old religious traditions makes Mount Ontake a destination with a distinctive character in every season.
Mount Ontake is much more than a high mountain. Its volcanic landscape, crater lakes, alpine plants, wildlife, waterfalls, pilgrimage routes, and sacred sites tell a story that has developed over hundreds and thousands of years.
For travelers interested in Japan’s natural landscapes, Mount Ontake offers spectacular mountain scenery. For those interested in culture and religion, its shrines, pilgrimage traditions, and sacred sites provide an opportunity to discover a distinctive form of Japanese mountain worship.
At the same time, because Mount Ontake remains an active volcano, visitors should always prioritize safety and check the latest official volcanic and trail information before traveling.