| Grandjean Peak | |
| Elevation Ft: | 9180. |
| Elevation Ref: | [1] |
| Prominence Ft: | 680. |
| Isolation Mi: | 2.51 |
| Isolation Ref: | [2] |
| Parent Peak: | Tohobit Peak (10,046 ft) |
| Listing: | Peaks of the Sawtooth Range |
| Etymology: | Emile Grandjean |
| Map: | Idaho#USA |
| Label Position: | bottom |
| Map Size: | 240 |
| Part Type: | Protected area |
| Part: | Sawtooth Wilderness |
| Country: | United States |
| State: | Idaho |
| Region: | Boise |
| Region Type: | County |
| Coordinates: | 44.1163°N -115.1043°W |
| Coordinates Ref: | [3] |
| Range: | Sawtooth Range Rocky Mountains |
| Rock: | Granite |
| Age: | Eocene |
| Type: | Fault block |
| Topo: | USGS Warbonnet Peak |
| First Ascent: | 1994 by Greg Parker |
Grandjean Peak is a 9180feet mountain summit in Boise County, Idaho, United States.
Grandjean Peak is part of the Sawtooth Range which is a subset of the Rocky Mountains.[4] This mountain with multiple high points is located 11 miles (18 km) southwest of Stanley, Idaho, in the Sawtooth Wilderness on land managed by Boise National Forest. Precipitation runoff from the mountain's slopes drains to the South Fork Payette River via Baron and Goat creeks. Topographic relief is significant as the summit rises 3580abbr=offNaNabbr=off above Baron Creek in one mile (1.6 km) and 3180abbr=offNaNabbr=off above Goat Creek in 0.85 mile (1.37 km).
The mountain is named after Emile Grandjean (1861–1942), who served as the first supervisor of Boise National Forest from 1908 to 1922.[1] This landform's toponym has been officially adopted by the United States Board on Geographic Names.[3]
Based on the Köppen climate classification, Grandjean Peak is located in an alpine subarctic climate zone with long, cold, snowy winters, and cool to warm summers.[5] Winter temperatures can drop below −10 °F with wind chill factors below −30 °F.