The list of sled dog races contains dozens of contests created by supporters of mushing, the sport of racing sled dogs. It is unknown when the first sled dog race was held. Humans have domesticated dogs for thousands of years, and sled dogs have been used for transportation in Arctic areas for almost as long. The first sled dog race to feature a codified set of rules was the All-Alaska Sweepstakes, which first took place in 1908. This was followed in 1917 by the American Dog Derby, which was the first sled dog race outside Alaska or the Yukon. In 1929 the Laconia World Championship Sled Dog Race" was first held in the city of Laconia, New Hampshire. The first race was won by legendary musher, Leonhard Seppala, famous for his role in the 1925 "Great Race of Mercy", as well as, his lead dog