In the two preceding seasons of 1909 and 1910, the Indianapolis Motor Speedway had run numerous smaller races across several meets per year. Declining crowds at the 1910 Labor Day meet convinced the four co-founders — Carl Fisher, James Allison, Arthur Newby and Frank Wheeler — that too many races had diluted public interest. They resolved to schedule a single, large-scale event for 1911. After deliberating between a 24-hour race and a 1,000-mile endurance contest, they settled on a 500-mile distance that would fit comfortably within daylight hours, starting at 10 a.m. and finishing in the late afternoon. Memorial Day, already the occasion of the largest previous crowds at the venue, was chosen as the date.
The entry fee was set at $500 per car — substantial enough to deter frivolous entries — and a total purse of $27,550 was offered, the largest in racing to that point. Forty cars ultimately qualified from 46 entries filed; two Falcar entries from Moline, Illinois failed to appear.
Forty cars lined up for the start, with grid positions determined by the date of entry filing rather than by speed — a deliberate departure from European practice. The field was drawn from both American and European manufacturers, with a minimum weight of 2,300 lb and a maximum engine size of 600 cubic inches.
Johnny Aitken, driving a National, led from the first row at the start, but was quickly overtaken by Spencer Wishart in a Mercedes and then by David Bruce-Brown in a Fiat, which dominated the opening half of the race. Tragedy struck on lap 12 when Sam Dickson, riding mechanic for Arthur Greiner, was thrown from the American Simplex car after a front wheel failed; Greiner survived with a broken arm, but Dickson was killed — the first fatality in Indianapolis 500 history.
Ray Harroun passed Bruce-Brown for the lead near the halfway point, driving his self-designed six-cylinder Marmon Wasp. Harroun famously raced without a riding mechanic — the standard practice of the era — mounting instead what is believed to be the first rearview mirror fitted to a racing car, though he later admitted the mirror vibrated so severely on the brick surface that it was largely useless. He was briefly relieved by Cyrus Patschke for approximately 35 laps before returning to the car and driving to victory. Harroun led 88 of the 200 laps — the most of any competitor — and won by approximately one minute and 42 seconds over second-placed Ralph Mulford in a Lozier. His race-average speed was 74.602 mph over a total elapsed time of 6 hours, 42 minutes and 8 seconds. Twelve of the 40 cars completed the full 500-mile distance; 14 cars dropped out through crashes or mechanical failure.
After the race, Mulford argued he had lapped Harroun during the period when Harroun limped in with a tyre failure, a claim made plausible by a crash that disrupted the official timing and scoring stand at approximately the same moment. Officials rejected the protest, noting that Mulford's own crew had spent several minutes hammering a bent rim during a subsequent pit stop, more than accounting for any disputed track position. Track historian Donald Davidson later noted that no formal protest was filed at the end of the race, and that Mulford offered Harroun public congratulations in the Detroit Free Press several days after the event.
Harroun's strategy — to run at a steady 75 mph pace regardless of position, reducing tyre wear compared with rivals running at 80 mph or faster — proved decisive. He made only three pit stops and changed four tyres in total; Mulford reportedly changed 14 tyres during the race.
The 1911 race immediately established the Indianapolis 500 as both the premier motorsports competition in the United States and one of the most prestigious in the world. The format of a single great race on Memorial Day proved extraordinarily durable, and the event has been held every year since — except for 1917, 1918, 1942–1945 — without fundamental change to its core concept. The rearview mirror that Harroun fitted to the Marmon Wasp, whatever its practical limitations in 1911, entered motorsport legend as an emblem of the technological ingenuity the race has always rewarded.