MINNEAPOLIS (WCCO) — The longest sled dog race in the lower 48 states started on Sunday near Two Harbors.

The John Beargrease Sled Dog Marathon features world class mushers. There are four defending champions racing this year in the 32nd running of the competition. More than 400 sled dogs and their mushers will race 383 miles up to Grand Portage and back to just north of Duluth.

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Organizers say the marathon has a big following.

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“We found that 2.9 million people followed this race either in the news or in social media. In one form or another, there were 2.9 million separate people following this thing,” Race Director Jason Rice said.

The race got its name in honor of John Beargrease, who used a sled dog team to deliver mail on the North Shore. If you’re thinking about going up to check out the race, organizers ask you to leave your pets at home so they don’t interfere with the musher’s dogs.

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The first crews are expected to cross the finish line Wednesday morning.