| Martyr River | |
| Source1 Location: | Olivine Range |
| Mouth Location: | Cascade River |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Length: | 20km (10miles) |
The Martyr River is a river of the West Coast Region of New Zealand's South Island. It flows generally northwest from its sources in the Olivine Range, joining its stream with the braided paths of the Cascade River 10 kilometres from the coast. New Zealand's Alpine Fault, the boundary between the Australian and Pacific tectonic plates,[1] is exposed in the banks of the Martyr River.[2]