Tunnel Hill Marathon
Race Day Weather
Cool start, gradual warming
Runners will face temperatures rising from 35°F at the start to 44°F by the finish. A light tailwind will assist from miles 1-7, but a headwind will challenge runners from mile 20 through 27. With humidity at 62%, maintaining hydration will be key, and runners should consider pacing conservatively to adapt to the gradual temperature increase.
Pace Calculator
Enter a finish time to see what race day does to it.
Get forecast alerts for Tunnel Hill Marathon
We'll text or email you when the forecast shifts — so you can adjust gear, pacing, and strategy. Max one per day.
Get your personalized Tunnel Hill Marathon race plan
A mile-by-mile breakdown of where your time goes, weather-adjusted splits, fueling timeline with aid stations, packing checklist, carb tracker, spectator guide, all built around your goal and race-day conditions.
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.
