|Basin countries||New Zealand|
|Mouth elevation||0 m|
|Basin area||670.36 km²|
The Mokihinui River is a river located on the West Coast of New Zealand's South Island, about 40 kilometres north of Westport. Meridian Energy had proposed the Mokihinui Hydro project on the river but it was cancelled in May 2012.
The Mokihinui River's headwaters are located in the Glasgow Range and its mouth is on the Tasman Sea. There is little human habitation near the river: the localities of Mokihinui and Summerlea are near the river's mouth, Seddonville is a few kilometres up the river, and just prior to its terminus, State Highway 67 crosses the river outside Mokihinui. In the rugged back country behind Seddonville at the Mokihinui Forks, the river splits into two branches, north and south. The catchment of these two branches is a large inland basin of almost wholly unmodified forest.
The river of interest for recreation and commercial whitewater activities. There is three hours of grade III water downsteam from where the north and south forks meet. A river level of 1-1.5 metres is an optimum flow.
The last few kilometres of the former Seddonville Branch railway roughly followed the Mokihinui River near its mouth. The Branch opened on 23 February 1895 and closed on 3 May 1981, while a further extension beyond Seddonville to Mokihinui Mine closed in February 1974.
During this period, the New Zealand Railways Department dumped two old steam locomotives along the river's banks between Seddonville and Mokihinui Mine to protect against erosion. The first of these locomotives, WB 292, was dumped in 1958, while sister WB 299 was dumped in January 1960. Both were recovered from the Mokihinui River in 1989 by the Baldwin Steam Trust, and are now owned by the Rimutaka Incline Railway.
- "Place Name Detail: Mokihinui River". New Zealand Geographic Placenames Database. Land Information New Zealand. Retrieved 23 June 2007.
- Buller District Council, Buller District Plan: Part 3 - The Management Environment, 17, accessed 24 June 2007.
- Egarr, Graham (1988). Whitewater River Running in New Zealand. Auckland: Reed Methuen. ISBN 0-474-00302-7.
- David Leitch and Brian Scott, Exploring New Zealand's Ghost Railways, revised edition (Wellington: Grantham House, 1998 ), 52-3.
- Baldwin Steam Trust, "Salvage Scheme", accessed 23 June 2007.