The 24 Hours of Le Mans takes place in Sarthe, the French department that contains the city of Le Mans and the Circuit de la Sarthe.
The race began in 1923 as an endurance test for cars and drivers, with the circuit using public roads south of the city. Its name reflects the Sarthe River, which runs through the department and near Le Mans. The modern circuit is a permanent-and-public-road combination, rather than a conventional closed racing venue.
A common mix-up is answering “Loire,” because the Loire Valley is nearby and the Loire is France’s best-known river. Calvados is farther northwest in Normandy, while Gironde is centered around Bordeaux. “La Sarthe” can also refer to the river, department, and racing circuit, but Sarthe is the department asked for here.