Fall Creek Beast
Swan Valley, United States • 31 Oct 2026
Fall Creek Beast - 50K and Half Marathon Trail Race
Fall Creek Beast is a trail running event on Halloween morning, October 31, 2026, in Swan Valley, Idaho. The race takes place at Rainbow Valley Ranch on Fall Creek Road. The event offers long and short trail options with significant elevation change.
- 50K: 6,000 ft elevation gain
- Half marathon (13.1 miles): 2,700 ft elevation gain
The location is about 35 minutes from Idaho Falls, 45 minutes from Rexburg, and roughly 1 hour from Jackson Hole. The organizers describe a focus on community and shared trail experiences, and entries are offered at roughly half the cost of a typical race. The race name refers to a local 1868 folklore creature from Swan Valley described in historical accounts as aquatic and snake-like, which inspired the event theme.
Race results from 2025 show 16 finishers in the 50K and 35 finishers in the half marathon. The course includes singletrack and open meadow sections around the Fall Creek area and features notable elevation changes that affect pacing and effort. Visit the organization's website for the most recent information.