Loud Thunder 50

APR
18
2026
Take on rugged single track at Loud Thunder Forest Preserve with 50 mile, 50K or half marathon looped courses that pack big elevation and scenic views. Two stocked aid stations and nearby camping make for a fun, community oriented trail weekend.
Sat 18 Apr 2026
50 miles 50 kilometers 13 miles

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Event

Loud Thunder 50 is a trail race at Loud Thunder Forest Preserve in Illinois City, IL (19408 Loud Thunder Rd). Distances offered:

  • 50 Miler
  • 50K
  • 1/2 Marathon

The event is organized by Quad Cities Trail & Ultra Runners and Sun Trail Running. Registration is online only. There are no refunds or bib transfers; a deferral policy offers 100% credit through February 18 and 50% credit through March 18. Packet pickup occurs on race morning and packets not picked up will not be shipped. Camping is available at the Horse Corral Campground and other park campgrounds; park campsite reservations open March 1 and have a two night minimum for online booking.

Course and logistics

The course is primarily a loop format with a full loop of 13.3 miles. The route is about 95% trail, consisting mostly of dirt single and double track, with short stretches of grass and crushed gravel 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. Loop directions differ by distance; the 50 miler runs three full loops plus a shortened fourth, the 50K two full loops plus a shortened loop, and the half marathon one loop.

Two fully stocked aid stations are provided; the longest gap between aid stations is less than 5 miles. Both aid stations allow drop bags and crew access. Pacers are allowed only for the 50 miler and only for the final ~18 miles. Race rules include Leave No Trace, no course cutting, trekking poles allowed, dogs not allowed, strict cutoffs, and no bib transfers. Visit the organization's website for the most recent information.

50 mi
50 Miles
50 km
50k
13 mi
1/2 Marathon

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