Tunnel Hill 100M
Race Day Weather
Cool start — fast day potential, big temp swing
A cool 40°F at the start line is ideal for fast times — expect to warm up quickly once you're moving. Temps will climb significantly to 57°F by later miles, so expect fading conditions as the race progresses. Light winds shouldn't be a major factor for pacing.
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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.
