The swampy Mangarakau Wetland is situated between the Whanganui Inlet and the Patarau River building the very northern tip of the Kahurangi National Park.
Covering an area of 350 ha, Mangarakau is home to many endemic bird, insect and plant species. The latter include the Gleichenia ferns, Baumea and Typha species in wetter regions, as well as endangered Myriophyllum robustum and Spiranthes sinensis.
Which was formerly used by the coal, timber, gold, wood and fishing industries, is now one the biggest protected swamplands in New Zealand. Only a few farmlands and touristic accomodations border the reserve.