December ultramarathons in Missouri, United States

Rugged Springfield trails, year-end atmosphere, festive gatherings, special recognition for back-to-back efforts

Challenging double-loop 50k from Krug Park to River Bluff, with steep bluff climbs above the Missouri River and rugged rolling dirt trail.

Compact loop course in Springfield, eight laps for the full marathon distance, late-season timing, supporting local charities