Loud Thunder 50
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Event overview
Loud Thunder 50 is a trail race day on April 18, 2026 at Loud Thunder Forest Preserve, Illinois City, IL. The start/finish area is at the Horse Corral Campground (park address: 19408 Loud Thunder Rd). The event offers the following distances:
- 50 Miler
- 50K
- 1/2 Marathon
Online registration is used; there is no paper or race-morning registration. The event is organized as a low-capacity trail race with custom finisher awards, post-race food and drink, and a guaranteed donation to the park. The race policy lists no refunds or bib transfers. Deferral credits are available with deadlines of February 18 (100%) and March 18 (50%).
Course and logistics
The course is based on a single full loop of about 13.3 miles. The 50 Miler runs the full loop three times plus a shortened fourth loop; the 50K runs the full loop twice plus a shortened loop; the half marathon runs a single loop. Terrain is approximately 95% trail, including dirt single and double track, short grass and crushed gravel sections, and minimal pavement. Approximate elevation gain is ~6600 ft for the 50 Miler, ~4000 ft for the 50K, and ~1900 ft for the half marathon.
Two fully stocked aid stations are on course; both allow drop bags and crew access. The longest distance between aid stations is under 5 miles. Pacers are allowed only for the 50 Miler and only for the final ~18 miles. Race rules require no cutting, leave no trace practices, and that runners remain on their registered distance. Visit the organization's website for the most recent information.