The 1955 U.S. Open was the 55th U.S. Open, held June 16–19 at the Lake Course of the Olympic Club in San Francisco, California. In one of the greatest upsets in golf history, Jack Fleck, a municipal course pro from Iowa, prevailed in an 18-hole playoff to win his only major title and denied Ben Hogan a record fifth U.S. Open. Fleck, 32, won two more titles on the PGA Tour and later won the Senior PGA Championship in 1979. He won the U.S. Open with clubs manufactured by Hogan's company.