| Forgotten River | |
| Pushpin Map: | New Zealand Fiordland#New Zealand South Island#New Zealand |
| Pushpin Map Size: | 270px |
| Pushpin Map Caption: | Mouth of the Forgotten River |
| Source1: | Forgotten River Col |
| Source1 Coordinates: | -44.4412°N 168.3442°W |
| Mouth Location: | Olivine River |
| Mouth Coordinates: | -44.476°N 168.2672°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Tributaries Left: | Blockade Stream, Milner Ice Stream |
The Forgotten River is located in northern Fiordland, New Zealand in Mount Aspiring National Park, and is a tributary of the Olivine River. The Forgotten River starts at the Forgotten River Col at the western edge of the Olivine Ice Plateau in the Five Finger Range. It flows south-westward to join the Olivine River as a hanging valley south of Four Brothers Pass.[1]
The river was explored in 1864 by Alphonse Barrington, James Farrell and Antoine Simonin. It is currently within the Olivine Wilderness Area which has limited aircraft access.[2]