The 9th International 500-Mile Sweepstakes Race was held at the Indianapolis Motor Speedway on Monday, May 30, 1921. Ralph DePalma dominated another early running of the 500, but again failed to win. He led 109 laps, and had a two-lap lead at the halfway point. A connecting rod broke, and he dropped out on lap 112. DePalma retired with one win, and 612 laps led in the "500." His laps led record would not be matched for 67 years until Al Unser, Sr. broke it in 1988.