Jigokudani Yaen Koen and its hot-spring snow monkeys
Published on 08/26/2026 at 14:29 | Editorial responsibility: Rafael Müller, Editor-in-Chief AD HOC NEWS
Jigokudani Yaen Koen, also known internationally as the Jigokudani Monkey Park, is a mountain valley enclosure in Yamanouchi where wild Japanese macaques descend to soak in a natural hot spring pool. The park sits in Nagano Prefecture inside Joshinetsu Kogen National Park, in a steep ravine carved by the Yokoyu River and edged by forests that stay snow-covered for long stretches of the winter.
Hot springs in a volcanic valley
The name Jigokudani means “Hell Valley”, a reference to the volcanic landscape of hot springs, exposed rock and columns of steam that rise from the ground in this corner of northern Nagano. The park stands at an altitude of about 850 m (2,789 ft) in the Yokoyu River valley, a side valley of the broader Shiga Kogen highlands within the Joshinetsu Kogen National Park.
The setting combines a steep-sided gorge, coniferous woodland and the milky water of an onsen source that feeds both a bathing pool for the monkeys and nearby human hot-spring towns such as Shibu and Yudanaka. This landscape has long been noted for its geothermal activity, and the established hot-spring culture in Yamanouchi forms the human backdrop to the monkey park’s location in the valley of the Yokoyu River.
From 1964 research ground to photographic icon
Jigokudani Yaen Koen opened in 1964 as a site where Japanese macaques could be observed in conditions close to their natural habitat, with particular attention to their social structure and behaviour in winter. The park’s formal Japanese name, Jigokudani Yaen Koen, reflects this origin as an enclosure or garden for wild monkeys rather than a conventional zoo, and it lies within the administrative area of Yamanouchi in Nagano Prefecture.
The combination of deep winter snow, rising steam and relaxed, wet-furred macaques has made the place a widely published image of Japan’s mountains. The animals are free-ranging residents of the surrounding forest and descend to the pool built beside the geothermal source, a scene documented in detail in guides to the Snow Monkey Park in the Yokoyu River valley. Photographs from the later twentieth century onwards have turned this specific pool, and the troop that uses it, into one of the most recognisable winter wildlife scenes associated with Nagano.
Japanese macaques in their mountain habitat
The residents of Jigokudani Yaen Koen are Japanese macaques, a species native to much of the country and known in English as snow monkeys when seen in snowy, highland regions. The animals live in social groups in the forested hills above the valley and move between the wooded slopes, the riverside and the hot-spring pool, making the park a place where human visitors can see primates that are neither domesticated nor confined to cages.
The monkeys’ relationship with the hot spring is a particular feature of this site. A hot pool fed by geothermal water has been created beside the steaming source, and it is here, in full view of the viewing path and wooden platforms, that macaques climb in to soak, especially during the colder months of the year. The park presents this behaviour as part of a wider story about the species’ adaptation to highland winters, with interpretive material and observation platforms set against the backdrop of the Jigokudani valley near Yamanouchi.
Visiting Jigokudani Yaen Koen: what travellers from Western Europe should know
- Jigokudani Yaen Koen lies in the mountains of Nagano Prefecture, north-east of the city of Nagano and within the municipality of Yamanouchi, which is linked to the wider rail network.
- The approach to the monkey park includes a maintained footpath through forest, with sections that can be narrow and snowy underfoot in winter and that require sturdy footwear.
- The valley stands at around 850 m (2,789 ft) above sea level, and in the colder months snow can cover both the path and the surrounding slopes, creating true winter conditions.
- Nearby onsen settlements such as Shibu Onsen and Yudanaka Onsen sit down the valley from Jigokudani Yaen Koen, offering a contrast between the monkeys’ outdoor pool and traditional human hot-spring baths.
- The official language is Japanese and the currency is the Japanese yen. Entry requirements depend on your nationality; UK travellers can check the FCDO travel advice at gov.uk/foreign-travel-advice, Irish travellers the Department of Foreign Affairs at ireland.ie.
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Frequently asked questions about Jigokudani Yaen Koen
Where is Jigokudani Yaen Koen?
Jigokudani Yaen Koen is in Yamanouchi, a town in Nagano Prefecture in central Honshu, within the Yokoyu River valley of Joshinetsu Kogen National Park.
What can visitors expect at the park?
Visitors walk along a forest path into a mountain valley to watch wild Japanese macaques around a hot-spring pool, with snow, steam and steep slopes as the backdrop.
What makes Jigokudani Yaen Koen distinctive?
The park’s defining feature is the sight of free-ranging Japanese macaques bathing in a geothermal pool amid a snowy landscape, framed by a volcanic gorge and hot-spring culture.
