American Bottoms 100
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Event overview
The American Bottoms 100 is a road ultramarathon held in Columbia, Illinois on March 21, 2026. The course follows the Mississippi River through the American Bottom and loosely follows the American Discovery Trail and the Kaskaskia - Cahokia Trail. The route passes historic sites such as Piggott's Fort, Fort de Chartres, and the town of Prairie du Rocher. Race headquarters are in Columbia, IL, near St. Louis, Missouri.
Course and distances
- 110 miles
- 55 miles
The course surface is approximately 76% levees and 24% hardball road. The 110-mile race is an out-and-back with about 1,400 ft of total elevation gain, 17 aid stations, and a 34-hour cut-off (implied pace 18:32 per mile). The 55-mile race is point-to-point with about 700 ft of elevation gain, 8 aid stations, and a 15-hour cut-off (implied pace 16:21 per mile). The event notes the use of levees and backroads along the river and lists multiple aid stations along each distance. A veteran and first responder discount of 15% is mentioned. Visit the organization's website for the most recent information.