The 66 mushers and their dog teams will spend roughly eight days trying to be the first to reach the old gold rush town of Nome.
"They look like this is what they live for," said Leigh Hopper, 53, a registered nurse from Hendersonville, Tenn., as she watched mushers get their dogs ready for Sunday's start. "They can't wait to get out there and run."
The grandsons of Iditarod Trail Sled Dog Race's co-founder Joe Redington were the first and last mushers on the trail.
Ray Redington Jr., 36, picked the first spot during the draw. He's competing in his 11th Iditarod and finished in seventh place last year. He said he hopes to do even better with his team, most of them veteran Iditarod dogs.
This year's competition is "tough, very tough," with the racing teams becoming more professional and serious about winning, he said. "They're getting better. So am I."
His younger brother, Ryan Redington, 29, is competing in his eighth race but had to wait to get on the trail after picking the last spot. He looked relaxed as he left the chute, actually sitting on the seat of his sled while smiling and waving to the crowds.
There are six former champions competing, including last year's winner, John Baker, 49, of Kotzebue, the first Inupiat Eskimo to win and first Alaska native since Jerry Riley in 1976.
Baker said that after winning last year's race on his 16th try, he considered retiring but realized there were too many people counting on him to run again.
When he isn't training for the race, Baker spends his time traveling to Alaska villages and giving Native children a message: Work hard, follow your dreams, and you can do it.
Kids treat him a bit differently now that he's an Iditarod champion. "They were quiet and listening for once," he said.
Also in the race is Lance Mackey, whose string of four consecutive wins was ended by Baker in 2011.
Mackey acknowledged feeling deeply disappointed by his 16th place finish last year. He has said he won't let himself feel that way again, no matter what the outcome, though he's in it to win it.
"This team is as good as any team here," Mackey said.
Organizers said the northern Iditarod route between Willow and Nome taken on even years is actually 975 miles, not as long as the 1,150 miles quoted in the past. However, some mushers believe the new estimate is too low and that the race is at least 1,000 miles.
Organizers cited various reasons for the mileage tweak, including the move of the competitive start north from Wasilla to Willow.
Brent Sass is competing in his first Iditarod but six times has run in the 1,000-mile Yukon Quest International Sled Dog Race -- considered by many to be a tougher race. A homemade sign atop his dog truck read, "Wild and Free. All the way to Nome."
"It is the Super Bowl of mushing," Sass said of the Iditarod. "It is the big one."
The total purse is $550,000 for the first 30 finishers, with the winner receiving $50,400 and a new truck.
Anjanette Steer, 39, is married to veteran Iditarod racer Zack Steer, but instead of looking from the sidelines this year she's the one taking the dog team to Nome.
"It is an adventure I will remember for the rest of my life," she said.