The Thumb is a 13,356-foot Sierra Nevada peak in the Palisades of northern California, within the John Muir Wilderness and Inyo National Forest. Ranked California’s 83rd-highest summit, it is notable for its steep local relief, with its east face rising more than 2,500 feet above Birch Lake in about a mile. The John Muir Trail passes below its southwest side. The mountain entered climbing history with Windsor B. Putnam’s first recorded ascent on December 12, 1921, and Norman Clyde’s first ascent of the class 4 northwest face on June 5, 1930. Putnam also proposed the name officially adopted in 1926. Its alpine environment feeds the Middle Palisade Glacier and drains toward Owens Valley.