The Mangapai River is a river of the Northland Region of New Zealand's North Island. It is perhaps better described as a silty arm of WhangÃÂrei Harbour, located due south of WhangÃÂrei. Its average width is some , but the silty nature of its course means that the stream itself is far narrower.
The New Zealand Ministry for Culture and Heritage gives a translation of "good stream" for Mangapai.