Aron Lee Ralston (born October 28, 1975) is an American outdoorsmanmechanical engineer and motivational speaker known for surviving a canyoneering accident by cutting off his own arm. During a solo descent of Bluejohn Canyon in southeastern Utahhe dislodged a boulder which pinned his right wrist to the side of the canyon wall. After five days he was able to amputate his arm with a dull pocketknife, make his way through the rest of the canyon, rappel down a 65-foot (20 m) drop, and hike 7 miles (11 km) to safety.[2][3]

The incident is documented in Ralston’s autobiography Between a Rock and a Hard Place and is the subject of the 2010 film 127 Hours where he is portrayed by James Franco.

After the accident he continued mountaineering and became the first person to ascend all of Colorado’s fourteeners solo in winter.