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 Togo and kennel dog Balto. The Laconia sprint race is an annual event today over 90 years later. In 1932, sled dog racing was a demonstration sport at the 1932 Winter Olympics in Lake Placid, New York, but was only included in one other winter olympics in a slightly different form of sled dog racing known as pulka. The most famous sled dog race is the Iditarod Trail Sled Dog Race, an annual 1000-mile race across Alaska. It commemorates the 1925 serum run to Nome. The first idea for a commemorative sled dog race over the historically significant Iditarod Trail was conceived Dorothy Page, the chair of the Wasilla-Knik Centennial Committee. Even though the race known today was not first run until 1973, thanks to the work of Joe Redington and his supporters. Joe Redington and the Iditarod helped restart worldwide interest in mushing, specifically in long-distance events. Since mushing's resurgence, the sport has proliferated and sled dog races are hosted in towns around the world, from Norway and Finland to Alaska and Michigan. Due to the cold temperatures needed for sled dog racing, most races are held in winter in cold climates, but occasional carting events, typically known as dryland races, have been held in warmer weather. Other similar sports that using mushing as a means for transport include; carting, pulka, dog scootering, skijoring, freighting, and weight pulling. These are not included in this list because they do not use sleds. A resurfaced race in 2020 is the Klondike Dog Derby, a 40-mile race