Yamanouchi Sanbonmatsu Onsen

Yamanouchi in Nagano is the home of Jigokudani Monkey Park, where wild Japanese macaques soak daily in outdoor geothermal pools throughout winter — one of the world's most photographed wildlife phenomena — and the Sanbonmatsu Onsen draws sulfated volcanic water from the same Shiga Kogen highland geothermal system that warms the monkeys' famous pool. The snow monkeys of Jigokudani have made Yamanouchi internationally famous, drawing visitors from every corner of the world who combine wildlife watching with soaking in the same warm volcanic mineral waters that comfort the macaques through Nagano's severe winters. The surrounding Shiga Kogen highlands form Japan's largest interconnected ski resort complex and were the venue of the 1998 Nagano Winter Olympics, framing the onsen in Japan's most extensive and historically significant alpine volcanic spa environment.