The 1956 Old Dominion 400 was a NASCAR Grand National Series (now Sprint Cup Series) event that was held on October 28, 1956 at Martinsville Speedway in Martinsville, Virginia. As a NASCAR-sanctioned "Sweepstakes" race, sedan vehicles from the Grand National Series and stock convertibles from the NASCAR Convertible division raced side-by-side with other for the same amount of money and championship points. By the 1990s, NASCAR's top-level series became a media circus that only races at facilities that are worth hundreds of millions of dollars.