Aron Lee Ralston (born October 27, 1975) is an American mountaineer, mechanical engineer, and motivational speaker, known for surviving a canyoneering accident in 2003 by cutting off part of his own right arm.
On April 26, 2003, during a solo descent of Bluejohn Canyon in southeastern Utah, he dislodged a boulder, pinning his right wrist to the side of the canyon wall. After five days, he had to break his forearm and amputate it with a dull pocket knife to break free. He then made his way through the rest of the canyon, rappelled down a 65-foot (20 m) drop, and hiked 7 miles (11 km) before being rescued.