|Basin countries||New Zealand|
|Length||20 kilometres (12 mi)|
The Mangatawhiri River is a river of the Auckland and Waikato Regions of New Zealand's North Island. It flows generally southwest from its sources in the Hunua Ranges southeast of Clevedon before flowing through a system of irrigation canals at the northern edge of the Waikato Plains close to the town of Pokeno. It reaches the Waikato River close to the township of Mercer.
The upper reaches of the Mangatawhiri are dammed to form reservoirs to store water for use by Auckland City.
It was here, that on the 12th of July, 1863, that under the orders of Governor Maori, starting the Waikato Land Wars
"Place Name Detail: Mangatawhiri River". New Zealand Geographic Placenames Database. Land Information New Zealand. Retrieved 12 July 2009.