The world's longest, toughest snowmobile race. Today’s Iron Dog course length 2,031 miles, starting in Big Lake to Nome following the Iditarod trail and finishing in Fairbanks, making it the World’s longest snowmobile race. Participants must traverse in some of Alaska’s the most remote and rugged terrain while confronting some the harshest winter conditions. Survival skills are essential, making it the World’s toughest snowmobile race. All teams in race classes are a team of two persons and two snowmobiles for safety.