Loud Thunder 50
Illinois City, United States • 18 Apr 2026
Event Overview
The Loud Thunder 50 is a trail running event scheduled for Saturday, April 18, 2026. The races take place at the Loud Thunder Forest Preserve in Illinois City, Illinois. The event offers three distances: a 50-mile, a 50 km, and a half marathon.
Course Details
The course is primarily a loop format, with each full loop measuring 13.3 miles. The terrain is approximately 95% trail, consisting of dirt single and double track, with some sections of grass and crushed gravel. There is minimal pavement. The races involve significant elevation gain: approximately 6,600 feet for the 50-mile, 4,000 feet for the 50 km, and 1,900 feet for the half marathon.
Logistics and Support
The start and finish area is located at the Horse Corral Campground. Camping is available at this location and at other campgrounds within the park; reservations can be made starting March 1st. Two fully stocked aid stations are provided, with the longest distance between them being less than 5 miles. Crew access is permitted at both aid stations. Pacers are only allowed for the 50-mile distance and only for the final 18 miles.
Rules and Registration
Online registration is required; there is no race morning registration. The event does not offer refunds or bib transfers. A deferral policy is available, with a deadline for 100% deferral by February 18. Time limits are enforced: 14 hours for the 50-mile, 12 hours for the 50 km, and 11 hours for the half marathon. A waitlist is maintained once the event reaches capacity. Visit the organization's website for the most recent information.