American Bottoms 100
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Event overview
The American Bottoms 100 is a road ultramarathon held Saturday, March 21, 2026, in Columbia, Illinois (11604 Bluff Rd), just outside St. Louis. The route runs along the Mississippi River and loosely follows the American Discovery Trail and the Kaskaskia - Cahokia Trail. The course passes historic sites including Piggott's Fort, Fort de Chartres, and the town of Prairie du Rocher. Registration closes Saturday, March 14 at 11:59 PM CT.
Distances
- 110 mile
- 55 mile
Race details
110 mile: 34 hour cut-off; total elevation gain 1,400 ft; out and back course; 76% levees and 24% hardball road; 17 aid stations; cut-off pace 18:32 minute per mile.
55 mile: 15 hour cut-off; total elevation gain 700 ft; point to point course; 76% levees and 24% hardball road; 8 aid stations; cut-off pace 16:21 minute per mile. Visit the organization's website for the most recent information.
