Worlds End 100K

Worlds End is a 100K and a 50K through the Endless Mountains, built around the Loyalsock Trail in Loyalsock State Forest and Worlds End State Park. Most of it is rocky single track. The longest sustained climb is only about 1,000 feet, but the short climbs never stop, and the 100K adds up to about 12,400 feet of gain. Along the way runners pass High Rock Vista, Canyon Vista and the Alpine View overlooks, the falls of the Ketchum Run gorge, and a wooden ladder beside Rode Falls.

The 100K starts at 5:00 a.m. from the Cliff Pavilion with 19 hours to finish, by midnight. The 50K starts at 7:00 a.m. with 12 hours, by 7:00 p.m., and climbs about 5,900 feet. The 100K is a Western States qualifier.

Both races start and finish at the Cliff Pavilion in Worlds End State Park. The course follows the Loyalsock Trail and the side trails that loop it back to the park, over technical, rock-strewn ground with a long run of short climbs. The organiser gives about 12,400 feet of gain for the 100K and about 5,900 feet for the 50K, and publishes no exact course length beyond the race names.

Entry is first-come on RunSignup, and it fills in minutes: the organiser says it has sold out in three to six minutes every year. The 100K needs a qualifier, a 50K or longer trail race finished inside its cutoff within three years of registering, and the race directors review every entry. Registration for 2027 opens at 6:00 p.m. on December 5, 2026. The 100K is $210 plus fees with a 200-runner cap, and the 50K $120 with a 250-runner cap. A wait list opens when a race fills, and an invitation off it has to be accepted within 48 hours.