Jack Powers (1827 – October 26, 1860), whose real name was John A. Power, was an Irish-born American outlaw who emigrated to New York as a child and later served as a volunteer soldier in the Mexican–American War in the garrison of Santa Barbara, California. During the California Gold Rush, he was a well-known professional gambler and a famed horseman in the gold camps as well as in San Francisco, Santa Barbara and Los Angeles.