Lake Mashū
| Lake Mashū 摩周湖 | |
|---|---|
Lake Mashū, Japan, during winter | |
| Location | Teshikaga, Kushiro Subprefecture, Hokkaido, Japan |
| Coordinates | 43°35′N 144°31′E / 43.583°N 144.517°E |
| Type | crater lake, endorheic |
| Primary inflows | two streams |
| Primary outflows | seepage |
| Catchment area | 32.4 km2 (12.5 sq mi) |
| Basin countries | Japan |
| Max. length | 6 km (3.7 mi) |
| Surface area | 19 km2 (4,700 acres) |
| Average depth | 137.5 m (451 ft) |
| Max. depth | 211.5 m (694 ft) |
| Water volume | 2.86 km3 (0.69 cu mi) |
| Shore length1 | 19.8 km (12.3 mi) |
| Surface elevation | 351 m (1,152 ft) |
| Frozen | December to April |
| Islands | Kamuishu Island |
| Settlements | none |
| 1 Shore length is not a well-defined measure. | |
Lake Mashū (摩周湖, Mashū-ko) (Ainu: Kamuy-to) is an endorheic crater lake formed in the caldera of a potentially active volcano. It is located in Akan Mashu National Park on the island of Hokkaido, Japan. It has been called the clearest lake in the world.