Which automobile club founded and organizes the 24 Hours of Le Mans?

The Automobile Club de l’Ouest founded and organizes the 24 Hours of Le Mans.

The French organization, commonly abbreviated ACO, traces its roots to the Automobile Club de la Sarthe, formed at Le Mans in 1906. It helped stage early motor races and later developed the idea of a round-the-clock endurance contest with secretary Georges Durand, journalist Charles Faroux, and tire manufacturer Émile Coquille.

The first 24 Hours of Le Mans took place on May 26–27, 1923. The event was designed to test reliability, fuel economy, speed, and mechanical endurance rather than simply determine the fastest sprint car. The ACO continues to run the race and manages the Circuit de la Sarthe, while working with the FIA on sporting and technical regulation.

IMSA organizes major North American sports-car championships, and the FIA is the international governing body for motorsport. Neither founded Le Mans. The Royal Automobile Club is a British organization associated with events such as the RAC Tourist Trophy, making it a plausible but incorrect alternative.