Tunnel Hill 100M
Race Day Weather
Comfortable temps, moderate wind, chance of rain
Mild 52°F temps at gun time mean comfortable early miles without overheating risk. Moderate winds around 15mph may affect pacing on open sections of the course. There's a chance of rain, so have a backup gear plan ready. High humidity (84%) will make it harder to cool down through sweat — increase fluid intake accordingly.
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Race Info
The Tunnel Hill 100 Mile runs the Tunnel Hill State Trail, a crushed-limestone rail-trail out of Vienna, Illinois, completing the race's 50-mile out-and-back loop twice between a southern turnaround at the Cache River State Natural Area's Wetlands Center and a northern turnaround beyond the community of Tunnel Hill, crossing the trail's namesake railroad tunnel four times. The route holds a grade under 2 percent over its converted rail-line profile. USATF and World Athletics certified, the race has produced multiple 100-mile world records, including Caitriona Jennings' 12:37:04 in 2025 and Camille Herron's 12:42:40 in 2017.
