The race is run in the middle section on an annual alternating northern and southern route around the Innoko National Wildlife Refuge. In even-numbered years, participants must complete the northern route; in odd-numbered years, since 1977, they must complete the southern route. Other than alternating routes, the course layout has changed only slightly since it was first held in 1973. Major changes have been the introduction of the restart and the change from Ptarmigan to Rainy Pass.
As a result of these conversions, the effective length of the route also varies. Officially, the actual length of the northern route includes 1112 miles (1790 km) and the southern 1131 miles (1820 km). However, often the length is given as 1049 miles in allusion to Alaska being the 49th state in the United States. For the actual course of the race, however, this is only of secondary importance, since the mushers are free to make their way between the individual checkpoints.
Checkpoints
Along the route to Nome there are 26 (northern route) and 27 (southern route) checkpoints, where the mushers have to report with their teams and where they can fill up the provisions and have a rest or change the sled. Otherwise the route choice is free. Once each participant must take a break of 24 hours, twice one of eight hours. This is to prevent that the dogs are overstrained. The health of the animals is also constantly checked by veterinarians.
Launch ceremony
| Ceremonial start |
| Anchorage to Eagle River 20 mi (32 km) |
| Highway (by car) |
| Eagle River to Willow 20 mi (32 km) |
| Restart |
| (ITC, Southern & Northern) |
The race begins the first Saturday of each March on Fourth Avenue in downtown Anchorage. Snow is dumped into the streets to make the start possible. For the teams that start here at two-minute intervals, this first stretch is special because there are plenty of spectators cheering on the competitors for the first 20 miles. However, some mushers fear that their dogs could become too nervous by it. Since according to the rules of the race this first section has no influence on the ranking, the participants often take it easy.
Start of timing
| Restart |
| Willow to Yentna Station 14 mi (23 km) |
| Yentna Station to Skwentna 34 mi (55 km) |
| Skwentna to Finger Lake 45 mi (72 km) |
| Finger Lake to Rainy Pass 30 mi (48 km) |
| Into the Interior |
| (ITC, Southern & Northern) |
The actual race usually starts in Willow on Sunday at 14:00. Participants start two minutes apart, and the gap at the start is credited to them later at one of the mandatory stops. There is an increased risk of incidents with elk during the first 100 miles, as they like to venture quite far south in search of food. Otherwise, the terrain is flat and the route is well marked. After Finger Lake, the route becomes more dangerous. Rainy Pass is considered the most difficult checkpoint of the race.
Into the hinterland
| Into the Interior |
| Rainy Pass to Rohn 48 mi (77 km) |
| Rohn to Nikolai 75 mi (121 km) |
| Nikolai to McGrath 54 mi (87 km) |
| McGrath to Takotna 18 mi (29 km) |
| Takotna to Ophir 25 mi (40 km) |
| Division of the route |
From Rainy Pass the route continues up, over the tree line and then down into the interior of Alaska. In the high valleys there is a constant threat of blizzards, which have also been the undoing of some participants. In 1974, there were several incidents of frostbite when the temperature reached -50 °F (-46 °C) in addition to winds blowing at 80 km/h (50 mph). The wind also obliterates the tracks and markers, making it even more difficult to stay on the trail. After the Rohn checkpoint, the trail follows the Kuskokwim River. Here the greatest danger is in so-called overflows, liquid water that flows almost invisibly above the frozen river.
The route continues via Nikolai, an Athabascan village, to McGrath, the largest checkpoint on this part of the route. Via Takotna the route leads to Ophir, from where it turns to the northern or southern route. At this point, the leaders are already several days ahead of the last.
Northern or southern route
| Northern route (even years) |
| Ophir to Cripple 59 mi (95 km) |
| Cripple to Ruby 112 mi (180 km) |
| Ruby to Galena 52 mi (84 km) |
| Galena to Nulato 52 mi (84 km) |
| Nulato to Kaltag 42 mi (68 km) |
| Reunion |
| (ITC, Northern) |
| Southern route (odd years) |
| Ophir to Iditarod 90 mi (145 km) |
| Iditarod to Shageluk 65 mi (105 km) |
| Shageluk to Anvik 25 mi (40 km) |
| Anvik to Grayling 18 mi (29 km) |
| Grayling to Eagle Island 60 mi (97 km) |
| Eagle Island to Kaltag 70 mi (113 km) |
| Reunion |
| (ITC, Southern) |
According to Ophir, the choice of route falls on the northern route in even years and the southern route in odd years. The southern route was first run in 1977, partly to pass through the namesake Iditarod town - now a ghost town - and also to give these towns the opportunity to be involved in the race. For many of the towns along the route, the Iditarod is the biggest event of the year, as they are virtually deserted except for a few Native Americans after the Alaskan gold rush ended.
The northern route leads via Cripple to Ruby on the Yukon River. Here, too, the best times are long gone. In 2007 only 169 people lived here, at the height of the 20th century there were almost 3000.
The southern route passes the ghost town of Iditarod and then heads to Eagle Island via Shageluk, Anvik and Grayling.
The route leads here over long distances along the Yukon and also on it. Again, the icy winds make the mushers create. To make matters worse, they are already suffering from lack of sleep and the route is very monotonous.
The routes eventually meet again in Kaltag. Off we go through the Kaltag Portage, a valley of the Unalakleet River, to Norton Sound.
Final spurt
| Reunion |
| Kaltag to Unalakleet 90 mi (145 km) |
| Final spurt |
| Unalakleet to Shaktoolik 42 mi (68 km) |
| Shaktoolik to Koyuk 48 mi (77 km) |
| Koyuk to Elim 48 mi (77 km) |
| Elim to Golovin 28 mi (45 km) |
| Golovin to White Mountain 18 mi (29 km) |
| White Mountain to Safety 55 mi (89 km) |
| Safety to Nome 22 mi (35 km) |
| Destination |
| Southern route: 1,131 mi (1,820 km) |
| Northern leg: 1,112 mi (1,790 km) |
| (ITC, Southern & Northern) |
While the last section of the Iditarod was rarely decisive in the past, as the race was usually already decided here, it has now become a final sprint. The course is now largely flat and the teams drive on the pack ice off the coast in some sections.
The route leads via Unalakleet, Shaktoolik, Koyuk, Elim and Golovin to White Mountain. There, the teams have to take another break of at least eight hours before they are allowed to set off for the final sprint to Nome.
This final section from White Mountain to Safety to the finish in Nome is really the final sprint of the race. Although times usually have to be given in days and hours rather than minutes and seconds, the fastest teams have often been separated by only a few minutes since the 1990s. It has happened that the second-placed team was only beaten by a second.
The finish line of the race is the Red "Fox" Olson Trail Monument, also just called burled arch, in Nome.
Fairbanks route
In 2003 and 2015, officials decided that the race would take place on the so-called Fairbanks route. After the ceremonial start in Anchorage, the race does not begin in Willow as usual, but in Fairbanks. This is because there is not enough snow on some of the sections to the south. Thus, for most of the route, it follows the desperate race to contain the 1925 diphtheria epidemic in Nome.