Waihou River
General data
- Name: Waihou River
- Water system: Pacific Ocean
- Water type: River
- Progression: Firth of Thames -> Hauraki Gulf -> Pacific Ocean -> Planet Earth
- Climates: Temperate
- Continents: Australia & Oceania
- Countries: New Zealand
The Waihou River is located in the northern North Island of New Zealand. Its former name, Thames River, was bestowed by Captain James Cook in November 1769, when he explored 14 mi (23 km) of the river from the mouth. An older Māori name was "Wai Kahou Rounga". A 1947 Geographic Board enquiry ruled that the official name would be Waihou.
The river flows north for 150 kilometres (93 mi) from the Mamaku Ranges past the towns of Putāruru, Te Aroha, Paeroa and Turua, before reaching the Firth of Thames at the south end of the Hauraki Gulf near the town of Thames.