Tunnel Hill Marathon
Race Day Weather
Cool start, gradual warm-up
Runners will face a temperature rise from 47°F at the start to 61°F by finish. With a light headwind from the SSW through miles 2-10, pacing adjustments may be necessary. The course profile is flat, but the tailwind from miles 17-26 will aid performance. Humidity is moderate, so runners should stay hydrated and consider a conservative start to manage the warming conditions.
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Race Info
Tunnel Hill Marathon is the shortest of four distances (100 mile, 100 km, 50 mile, and marathon) run together each November on the Tunnel Hill State Trail, a crushed-limestone rail-trail out of Vienna, Illinois that passes through a historic railroad tunnel. The course holds between 340 and 680 feet of elevation with a grade under 2 percent, and the event has produced multiple USATF and world records at the 50-mile and 100-mile distances, including Caitriona Jennings' 12:37:04 100-mile world record set in 2025. The marathon serves as a Boston-qualifying option for runners who want a shorter distance than the ultra events held the same day.
