Gero is a hot-spring town in the Hida valley of Gifu Prefecture, about an hour south of Takayama by train. The town follows the Hida River, with ryokan, foot baths, bridges, and steep green hills keeping the onsen mood close to the surface.
The water is the reason to come. Gero Onsen has long been counted among Japan's famous hot springs, and even a short visit lets you try public baths or the free foot baths around town. The relaxed rhythm matters more than a checklist.
There is still enough to do between soaks. Onsenji Temple looks down over the river valley, Gero Onsen Gassho Village gives a compact look at steep thatched farmhouses from the mountain region, and the Gero Onsen Museum explains the water rather than just selling it. Gero is best as an overnight, but it can also be a good slow day between Nagoya and Takayama.