Sulphur Springs Trail Race 100K

Five loops of the 20K Dundas Valley circuit total 100K with 2,600m of cumulative elevation gain. The event is Ontario's only WSER qualifier at the 100K distance — sub-18-hour finishers earn a ballot for the Western States Endurance Run lottery. Crew access at the start/finish after each loop, a bag drop station, and four fully stocked aid stations keep runners supported through the day and into the night.