• The Arrowhead 135 is recognized in the book "The World's Toughest Endurance Challenges" by Richard Hoad and Paul Moore as one of the 50 toughest races in the world.  It is a human powered Ultra Marathon taking place in the coldest part of winter in the coldest city in the lower 48 states.  Our average finish rate is less than 50%, the finish rate for new racers is much lower.  2014 finish rate was 35%.   135 miles Deep Winter across Northern Minnesota on rugged, scenic Arrowhead State Snowmobile Trail from Frostbite I-Falls...