| Kaihu River | |
| Mouth Location: | Wairoa River |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Length: | 38km (24miles) |
The Kaihu River is a river of the far north of New Zealand's North Island. It originates in native forest near Trounson Kauri Park[1] flows southeast from just south of Waipoua Forest, reaching the Wairoa River at the town of Dargaville.
Its surrounding land supports a combination of forestry (both native and exotic), agriculture, and horticulture, though dairy farming is the primary land use in the mid to lower sections. The river is also notable for having volcanic acidic catchment geology, a feature shared with five other locations in the area.[2]