The Inangahua River is located in the northwest of New Zealand’s South Island. It is a major tributary of the Buller River, which it joins at the town of Inangahua Junction. The Inangahua River begins near the Rahu Saddle and flows northwest for 35 kilometres (22 mi), followed by State Highway 7, to the town of Reefton. The Reefton Power Station, now decommissioned, operated with water taken from the river from 1888 to 1949. At Reefton it turns north and continues for 30 kilometres (19 mi), passing Cronadun, before reaching the Buller some 40 kilometres (25 mi) from the larger river's outflow into the Tasman Sea near Westport. The Inangahua's tributaries include the Waitahu River, Te Wharau River and Awarau River.