Corps of Discovery Trail Races

Corps of Discovery Trail Races, hosted by the St. Louis Track Club, take place in the Weldon Spring Conservation Area near Saint Charles, Missouri. Runners choose from a 5-mile Clark Trail loop, an 8-mile Lewis Trail loop, or a Half Marathon that combines both trails for about 13.1 miles.

The course winds along Missouri River bluffs and hardwood ridges on trails that are open to other users and runs counterclockwise. Markings and volunteers assist at splits, and the event uses cup-free aid stations. Early registrants receive a T-shirt and finisher medal.

A new 8-mile option was added in 2025, with Tailwind Nutrition as sponsor. Visit the organization's website for the most recent information.