The National Association of Formula One Racing (NAFOR) is the largest professional racing association in the United States and the second largest Formula One league in the world. The NAFOR sponsors the American Grand Prix Series yearly, which is a series of 24 races, capped by the Indianapolis 500 at the start of the season, the Daytona 500 at the middle of the season, and the Sequoyah 500 as the final race of the season.