This entire marathon takes place at 10,000 feet above sea level or higher

Running a marathon is hard enough, but running a marathon with a peak elevation of 13,185 feet... that's reserved for some of the toughest endurance athletes around.

Set to take place on June 18, the Leadville Marathon, presented by La Sportiva, is the 'highest trail marathon in America,' traveling mostly old mining roads and trails. It tops out at 13,185 feet of elevation on Mosquito Pass, which happens to be the highest continuous mountain pass in the country.

While other trail marathons may reach a higher peak elevation – specifically the Pikes Peak Marathon, which climbs to the 14,115-foot summit of 'America's Mountain' – the Leadville Marathon's claim to fame is that it's got the highest starting line in the country, at roughly 10,000 feet above sea level. From that point on, the race never drops below that elevation.

While there's a chance that snow may be present at this elevation, course officials expect the warm weather that's anticipated leading to race day, along with work done by crews, to get the path mostly clear.

Racing at this elevation means a number of hazards not typically faced by runners. Thinner air will make it harder to breath and weather can be unpredictable, often windy and cold during any season of the year.

The marathon won't be the only race taking place on Saturday, either, with a 'heavy half' also planned. While the typical half marathon takes place on a 13.1-mile course, this 'heavy half' will be 15.46 miles long, following much of the same route as the full marathon, also reaching the elevation of 13,185 feet.

While these races are already sold out for this year, it's sure to bring a lively atmosphere to the tiny mountain town of Leadville that will be worth checking out.

Find out more information about the happenings this weekend here.

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