The Mahurangi River is a tidal estuary in northern New Zealand that widens into the Mahurangi Harbour before opening into the outer Hauraki Gulf. The Mahurangi Harbour is accessible by all craft and is a sheltered anchorage in all weathers with many small bays and islands. The river itself is extremely tidal and ranges in depth from below approximately 50 cm (MLW) at the channel entrance to approximately 150 cm (MLW) further up stream.