The 100-mile ultramarathon — 161km — is the stuff of trail-running legend, the distance where the sport's toughest battles are fought and won. Inspired by the original Ultra-Trail du Mont-Blanc, a miler typically means a full day and night (or more) on the move, climbing tens of thousands of feet through mountains and wilderness, running through sunset, darkness and sunrise to reach the finish. In Australia, the KosciMiler at Ultra-Trail Kosciuszko by UTMB leads the way, sending runners deep into the alpine high country of the Snowy Mountains. Finishing 100 miles demands meticulous preparation, race-day patience, a solid crew and pacer plan, and serious mental resilience — but few achievements in running compare. For elite runners it's a shot at UTMB Running Stones and a path toward UTMB Mont-Blanc; for everyone else, it's the ultimate personal Everest.

Find 100-mile ultramarathons across Australia below by date and state.