Both the 100K and 100-mile races at OSJ ONTAKE100 begin in darkness, directing participants into the national forest at the base of Mt. Ontake. This long-distance trail event takes place in Ontake Village, utilizing forest roads situated below the 3,067-meter sacred peak.
The course incorporates unpaved forest roads typically restricted from public access, offering runners entry to normally off-limits terrain on race day. Previously known as OSJ Ontake Ultra Trail 100K, the event is presented by PowerBar.