Zao Onsen is a well known hot spring and ski resort near Mount Zao, Japan.
The resort is made up of various onsen hotels resorts. During the winter, it is one of only a few places in Japan where "ice trees" can be seen. Also known as "snow monsters", the trees take on curious shapes due to the heavy snowfall and freezing winds.
The Hinata residents briefly stay in one of the hotels in the resort while pursuing Naru who was running away from her relationship with Keitaro.
The Zao Onsen was based on the Nishiya Ryokan in Yonezawa City. The building has a 200-year history.