The 1931 U.S. Open was the 35th U.S. Open, held July 2–6 at Inverness Club in Toledo, Ohio. Billy Burke won his only major title, defeating George Von Elm in a marathon 72-hole playoff, the longest in tournament history.
Von Elm, the 1926 U.S. Amateur champion, held the 54-hole lead at 217 after rounds of 75-69-73. Burke, playing just ahead of Von Elm in the final round, carded a 73 and a 292 total. Von Elm bogeyed 12, 14, 15, and 16, and needed a birdie at 18 to force a 36-hole playoff on Sunday.
In the playoff, Von Elm and Burke were still tied after 36 holes, with Von Elm making a birdie on the 36th to extend it. In the era prior to sudden-death, 36-hole playoffs were required to break ties, so another was held the following day.
In the morning round, Von Elm shot a 76 and led by a stroke, but Burke took the lead late in the afternoon round at the 32nd and extended it to two strokes at the 34th. A bogey on the final hole narrowed Burke's victory margin to one stroke, 148 to Von Elm's 149. Burke reportedly smoked 32 cigars during the tournament, and quipped afterwards: "George Von Elm lost 15 pounds (7 kg). I gained three."
Following this tournament, the USGA reduced the length of all future playoffs to 18 holes, which remains the format to the present day. A second playoff round was played in 1939 and 1946. Sudden-death after 18 holes was added in the 1950s, but was not needed until 1990, and was used again 1994 and 2008.
Leo Diegel made a hole-in-one during the second round, only the third in U.S. Open history and first since 1922. He missed the playoff by two strokes and finished in third place. Low-amateur went to Philip Perkins, who finished in a tie for seventh. Three-time British Open champion Henry Cotton played the first of two U.S. Open appearances this year, missing the cut. Defending champion Bobby Jones retired from competition in 1930 and did not compete.
This was the second U.S. Open at Inverness, which hosted eleven years earlier in 1920. It later hosted in 1957 and 1979, and the PGA Championship in 1986 and 1993.