Snow Monkey Park

Jigokudani Monkey Park is located in Yamanouchi, Nagano Prefecture, Japan. It is part of the Joshinetsu Kogen National Park, and is located in the valley of the Yokoyu-River, in the northern part of the prefecture. The name Jigokudani, meaning "Hell's Valley", is due to the steam and boiling water that bubbles out of small crevices in the frozen ground, surrounded by steep cliffs and formidably cold and hostile forests.The heavy snowfalls, an elevation of 850 m, and being only accessible via a narrow 2 km footpath through the forest, keeps it uncrowded despite the park being relatively well known.

It is famous for its large population of wild Japanese macaques, more commonly referred to as snow monkeys, that go to the valley during the winter, foraging elsewhere in the national park during the warmer months. The monkeys descend from the steep cliffs and forest to sit in the warm waters of the onsen, and return to the security of the forests in the evenings.