(1869-c. 1908) the leader of a group of criminals in the American Wild West called the 'Wild Bunch' or the 'Hole-in-the-Wall Gang'. Another member of the group was Harry Longbaugh, also called the 'Sundance Kid'. They robbed trains in Wyoming. Both Cassidy and Longbaugh disappeared to Bolivia and may have died there. Their story was told in the 1969 film Butch Cassidy and the Sundance Kid with Paul Newman and Robert Redford.