| Mu River | |
| Name Other: | 鵡川 |
| Subdivision Type1: | Country |
| Subdivision Name1: | Japan |
| Subdivision Type2: | State |
| Subdivision Name2: | Hokkaido |
| Subdivision Type3: | Region |
| Subdivision Name3: | Iburi, Kamikawa |
| Subdivision Type4: | District |
| Subdivision Name4: | Yūfutsu |
| Subdivision Type5: | Municipalities |
| Subdivision Name5: | Mukawa, Shimukappu |
| Length: | 135km (84miles) |
| Discharge1 Avg: | 50.44m3/s |
| Source1: | Mount Karifuri |
| Source1 Location: | Shimukappu, Hokkaido, Japan |
| Source1 Coordinates: | 43.0281°N 142.6844°W |
| Source1 Elevation: | 740m (2,430feet) |
| Mouth: | Pacific Ocean |
| Mouth Location: | Mukawa, Hokkaido, Japan |
| Mouth Coordinates: | 42.5625°N 141.9169°W |
| Mouth Elevation: | 0m (00feet) |
| Basin Size: | 1270km2 |
is a river in Hokkaido, Japan. Located in Kamikawa and Iburi subprefectures, it is one of 13 Class A rivers on the island.
The Mu River rises on the slopes of Mount Karifuri in the Hidaka Mountains.[1] It flows south and west until it reaches the Pacific Ocean at Mukawa.
| Class 1 river name | Class 2 river name | Name | Height (m) | Water storage capacity (per 1000 m3) | Type | Operator | |
|---|---|---|---|---|---|---|---|
| Mu River | Soshubetsu River | Soshubetsu Dam | 29.0 | 1,330 | Concrete | Hokkaido Electric Power Company | |
| Mu River | Hobetsu River | Hobetsu Dam | 38.2 | 10,330 | Rockfill | Hokkaido Regional Development Bureau |
Shimukappu (upper reaches):
Mukawa (lower reaches):