The Ironstone 100K 2026 is a renowned trail running event held annually in the rugged and scenic terrain of Pennsylvania. Organized by Eastern States Trail Endurance Alliance (Eastern States 100) and Allegheny Trail Runners Inc., this event challenges runners with its demanding routes, combining the beauty of the landscape with the rigors of trail running. The Ironstone 100K 2026 has gained a reputation and it draws runners from across the nation who are eager to test their endurance and skills in one of the most picturesque and challenging settings available in the trail running circuit. Strambecco rates Ironstone 100k as one of the Best Trail Running Race Events in the Mid-Atlantic and one of the Best Trail Running Race Events in Pennsylvania.

The Ironstone 100K is a demanding point-to-point ultramarathon spanning 100 kilometers through the rugged trails of the Alleghenies. Starting at Canoe Creek State Park and finishing at Greenwood Furnace State Park, the race features minimal aid stations, no pacers, and begins at 2 p.m. Its unforgiving technical terrain includes ridge running on Tussey Mountain and navigating old-growth pines, craggy ledges, and historic paths. Runners must complete the course within 23 hours, earning a unique metal award, a finisher flannel shirt, and post-race refreshments.

The route encompasses approximately 62 miles (100 kilometers) of challenging terrain with an elevation gain of around 6,500 feet. Runners will traverse dense forests, open fields, and rugged backcountry trails, encountering various terrain challenges that demand technical skill and endurance.

Minimal aid stations are strategically positioned along the route, typically every 15-20 miles, stocked with water, nutrition, and first aid supplies. The event prioritizes safety with a participant limit of 150 runners. The finish rate for the event has ranged between 50-60% the past few years.

Starting at 2pm, the event offers awards for top finishers across various categories, including overall placement, age groups, and gender. While welcoming runners of diverse skill levels, prior experience in endurance trail running events is required.

Eastern States Trail-Endurance Alliance also produces the famed Eastern States 100, which is a qualifier for the Western States 100, in addition to the Eagleton Trail Challenge.