The Boulder River is a small river in the north of the South Island of New Zealand.
| Boulder River | |
|---|---|
 Route of the Boulder River | |
.png)  Mouth of the Boulder River   Boulder River (New Zealand) (South Island) | |
| Location | |
| Country | New Zealand |
| Physical characteristics | |
| Source | |
| • location | Boulder Lake |
| • coordinates | 40°53′21″S 172°34′30″E / 40.8893°S 172.575°E |
| • elevation | 985 metres (3,232 ft) |
| Mouth | |
• location | Aorere River |
• coordinates | 40°48′09″S 172°32′56″E / 40.80244°S 172.54875°E |
| Basin features | |
| Progression | Boulder River → Aorere River → Ruataniwha Inlet → Golden Bay / Mohua → Tasman Sea |
| Tributaries | |
| • left | Amphitheatre Creek |
| • right | Parson Creek |
The headwaters are at the Kahurangi National Park's small Boulder Lake. The river flows north for 10 kilometres (6 mi) before draining into the Aorere River.