The Hangaroa River is a river in the Gisborne and Wairoa districts of New Zealand. Its source is the Huiarau Ranges in Te Urewera and Waikareti North Conservation Area, and flows southeast to merge with the Ruakituri River near Te Reinga. After Te Reinga Falls, the Hangaroa River flows into a basin which is the start of the Wairoa River. The Wairoa River flows south into Hawke Bay.