Mystery Mountain Marathon & 12-Miler
Chatsworth, United States • 18 Oct 2026
Event details
The Mystery Mountain Marathon and 12-Miler takes place at Fort Mountain State Park in Chatsworth, Georgia on Sunday, October 18, 2026. Distances offered:
- Marathon
- 12 Mile
The marathon route includes about 5,500 feet of total elevation gain. The event is produced by a volunteer nonprofit and a portion of proceeds supports Fort Mountain State Park. There is a $10 state park parking fee in effect; an annual park pass may be used in lieu of the daily fee. Combined race entries are limited to 250 participants. Shirt size is guaranteed only for entries received before September 19.
Course and support
Both courses start with a loop around the lake and use a mix of single-track, rugged mountain bike trails, and smoother horse trails. Key trails include Big Rock and the Gahuti, plus a loop atop Fort Mountain that passes a historic low rock wall. The marathon adds the 301 loop before returning to the lake. Trail markings: 12-Miler follows orange markers; marathon follows orange for the first 11 miles and then blue markers after the Power Line aid station. Aid stations: the 12-Miler has three full aid stations plus one fluids-only; the marathon has six full aid stations plus two fluids-only. Cutoffs: 12-Miler 6-hour limit with a 3.5-hour checkpoint at the park entrance (approx 8 miles); marathon 8-hour limit with multiple midcourse cutoffs. Bears have been spotted on sections of the course; runners should be aware of wildlife. Visit the organization's website for the most recent information.