Matsukawa Onsen (松川温泉) is a small, remote hot spring town on the Iwate side of Mount Hachimantai within Towada-Hachimantai National Park. It consists of just a handful of ryokanalong a river with baths fed by the local, sulfurous and slightly cloudy hot spring water. All ryokan open up their baths to non-staying guests during the day for a small fee.
A little upriver from the hot springs stands the Matsukawa Geothermal Power Station. Built in 1966, this was the first geothermal power plant in Japan, and it supplies both clean energy and hot water to the region. The plant and its 45 meter high cooling tower cannot be entered; however, there is a small visitor center with a video and displays about the plant’s construction and operation.