Iditarod Trail Sled Dog Race early in the 20th century. The main route of the Iditarod trail extends from Seward in the south to Nome in the northwest, and was first surveyed by Walter Goodwin in 1908, and then cleared and marked by the Alaska Road Commission in 1911 and 1912. The entire network of branching paths covers a total of . Except for the start in Anchorage, the modern race follows parts of the historic trail. The trail is composed of two routes: a northern route, which is run on even-numbered years, and a southern route, which is run on odd-numbered years. Both follow
Iditarod Trail Sled Dog Race narrow Happy River Gorge, where the trail balances on the side of a heavily forested incline. Rainy Pass is the most dangerous check point in the Iditarod. In 1985, Jerry Austin broke a hand and two of his dogs were injured when the sled went out of control and hit a stand of trees. Many others have suffered from this dangerous checkpoint. Rainy Pass is part of the Historic Iditarod Trail, but until 1976 the pass was inaccessible and route detoured through Ptarmigan Pass, also known as Hellsgate, because of the 1964 Good Friday earthquake. From Rainy Pass, the route