The Arrowhead 135 Mile Winter Ultra Race, set for January 26, 2026, in International Falls, MN, stands as a formidable challenge consistently ranked among the world's toughest endurance events. This grueling 135-mile human-powered ultramarathon pushes athletes on foot, skis, or bicycles across the frozen landscapes of Northern Minnesota, beginning at Kerry Park arena in International Falls and culminating at Fortune Bay Casino in Tower. Known as the "Icebox of the Nation," International Falls lives up to its moniker, with typical race day conditions seeing highs around 16°F and lows plunging to -6°F, though temperatures can plummet far lower, even to -45°F (-43°C) or -60°F. A mere 2% chance of precipitation means the challenge primarily lies in battling the profound cold and the vast, often solitary wilderness.

The course unfolds along the rugged, scenic Arrowhead State Trail, a multi-purpose snowmobile route that offers a diverse and demanding journey. The northern section presents a relatively flat expanse between International Falls and the Ash River, while the southern part transforms into a series of rugged, rolling hills, dotted with numerous lakes, streams, exposed rock, and enormous glacial boulders. Competitors navigate wide, well-groomed, and meticulously marked trails, traversing heavily timbered areas with a mix of hardwoods and conifers, and are often treated to sightings of local wildlife like moose, wolf tracks, deer, lynx, and fox. With over 6,400 feet of elevation gain, the terrain is genuinely hilly, especially the relentless 40-mile stretch of hills after the MelGeorge's Elephant Lake Resort checkpoint around mile 72.

What truly sets the Arrowhead 135 apart is its extreme self-supported nature. Racers must carry extensive survival gear, including camp stoves and sleeping bags, as outside aid is severely limited to just three checkpoints along the entire 135-mile route. Shelters are sparsely distributed, with the longest gap between them being 23 miles, forcing athletes to confront the wilderness and their inner resilience. This commitment to self-sufficiency contributes to the race's notoriously low finish rate, often below 50% and even lower for first-time participants. The profound solitude, broken only by the crunch of snow or the occasional howl of a wolf, creates an intense mental and physical crucible, offering a unique wilderness adventure where the true reward is often found in the camaraderie and the personal triumph of simply participating.