The Tongariro River is New Zealand's most fished river, flowing into Lake Taupō in the Waikato region. It is a renowned year-round fishery managed under strict regulations to preserve its world-class trout population. The river is characterized by its clear, freestone waters, diverse structure, and a mix of rainbow and brown trout known for their impressive size and fighting ability. Angling is fly-fishing only, with specific rules governing techniques and boat use, particularly in the lower sections. Access is well-established through public tracks and reserves, though wading can be challenging due to the river's powerful flow and slippery, boulder-strewn bed.