| The Thumb | |
| Other Name: | East Palisade |
| Elevation Ft: | 13356 |
| Elevation Ref: | [1] |
| Prominence Ft: | 594 |
| Isolation Mi: | 0.93 |
| Isolation Ref: | [2] |
| Parent Peak: | Ed Lane Peak (13,577 ft) |
| Listing: | Sierra Peaks Section |
| Map: | California#USA |
| Map Size: | 260 |
| Label Position: | bottom |
| Location: | Inyo County, California, U.S. |
| Range: | Sierra Nevada Palisades |
| Coordinates: | 37.0715°N -118.446°W |
| Coordinates Ref: | [3] |
| Topo: | USGS Split Mountain |
| Rock: | granitic |
| Age: | Cretaceous |
| Type: | Fault block |
| First Ascent: | 1921 |
| Easiest Route: | Southeast slope |
The Thumb is a 13356feet mountain summit located on the crest of the Sierra Nevada mountain range, in Inyo County of northern California.[3] It is situated in the Palisades area of the John Muir Wilderness, on land managed by Inyo National Forest. It is 1.3miles east of Middle Palisade, 1.6miles west-northwest of Birch Mountain, and 1.8miles north of Mount Bolton Brown. The Thumb ranks as the 83rd-highest summit in California.[2] Topographic relief is significant as the east aspect rises over 2500abbr=offNaNabbr=off above Birch Lake in approximately one mile. The John Muir Trail traverses below the southwest aspect of the mountain, providing an optional approach access.
The first ascent of the summit was made December 12, 1921, by Windsor B. Putnam via the southeast slope and an approach from Birch Creek. The northwest face was first climbed June 5, 1930, by Norman Clyde.[4] This mountain's name was submitted for consideration by Windsor B. Putnam, and officially adopted in 1926 by the U.S. Board on Geographic Names.[3] This peak has in the past been called "East Palisade" and "Thumb Peak".[3]
The Thumb has an alpine climate which supports the Middle Palisade Glacier below the western cliffs.[5] Most weather fronts originate in the Pacific Ocean, and travel east toward the Sierra Nevada mountains. As fronts approach, they are forced upward by the peaks, causing them to drop their moisture in the form of rain or snowfall onto the range (orographic lift). Precipitation runoff from this mountain drains to Owens Valley via Big Pine and Birch Creeks.