| Castle Lake | |
| Location: | Custer County, Idaho |
| Coords: | 44.0463°N -114.5766°W |
| Lake Type: | Glacial |
| Outflow: | Little Boulder Creek to East Fork Salmon River |
| Basin Countries: | United States |
| Length: | 288m (945feet) |
| Width: | 266m (873feet) |
| Elevation: | 2875m (9,432feet) |
| Pushpin Map: | Idaho#USA |
| Pushpin Map Alt: | Location of Castle Lake in Idaho, USA. |
Castle Lake is an alpine lake in Custer County, Idaho, United States, located in the White Cloud Mountains in the Sawtooth National Recreation Area. The lake is accessed from Sawtooth National Forest trail 047.[1]
Castle Lake is just north of Castle Peak and south of Merriam Peak. It is upstream of Baker Lake.