Iditarod Trail Sled Dog Race to the 2010 census, it has a population of 401, making it the largest checkpoint in the Interior. McGrath is also notable for being the first site in Alaska to receive mail by aircraft (in 1924), heralding the end of the sled dog era. It still has a good airfield, so journalists are common. Following McGrath is Takotna, formerly a commercial hub during the gold rush. The ghost town of Ophir, named for the reputed source of King Solomon's gold by religious prospectors, is the next checkpoint. By this stage in the race, the front-runners may be several days ahead
Iditarod Trail Sled Dog Race reveals the results of tests on the dogs. Each team is composed of twelve to sixteen dogs, and no more may be added during the race. At least five dogs must be on the towline when crossing the finish line in Nome. Mushers keep a veterinary diary on the trail and are required to have it signed by a veterinarian at each checkpoint. Dogs that become exhausted or injured may be carried in the sled's "basket" to the next "dog-drop" site, where they are transported by the volunteer Iditarod Air Force to the Hiland Mountain Correctional Center at Eagle River