River, North Island , New Zealand.
Rising on the slopes of Mount Ruapehu as the Tongariro River, it flows north through Lake Taupo , then northwest to enter the Tasman Sea . The nation's longest river, it is 264 mi (425 km) long and is a major source of hydroelectric power. It was the scene of several skirmishes between the British and the Waikato tribes in 186365.