Ontario's only WSER qualifier — 8 loops of Carolinian forest since 1992
Other trail races within 187 miles
Canada's oldest ultramarathon takes runners on eight 20K loops through the Dundas Valley Conservation Area, accumulating 4,160m of elevation gain on a mostly double-track Carolinian forest circuit. Natural springs, waterfalls, and old-growth hardwood canopy line the course as runners pass through the start/finish crew area after each loop. The final laps unfold after dark, with pacers joining from the 7th loop onward. As Ontario's only WSER qualifying race, sub-30-hour finishers earn a lottery ballot for the Western States Endurance Run, making this loop race punch well above its weight on the ultra calendar.
Some ultra experience recommended
Hamilton, ON, CanadaMay 29, 2027
Sulphur Springs Trail Race 100 Mile is a multi-loop trail race in Hamilton, ON, Canada, held on May 29, 2027. The course covers 160 km, climbs 4,160 m, and has a 30h cutoff.
This edition has its own course and we haven't mapped it yet. The interactive map, elevation profile and aid stations will appear here once the route is confirmed.
Aid stations for this edition aren't published yet. They'll appear here once the route is confirmed.
No overnight camping at the race site. Crew tents are allowed on the grassy area behind the main race tents at the start/finish area on a first-come, first-served basis (no electricity or running water). RVs/trailers not permitted. Hotels and motels available in Hamilton, Ancaster, and Burlington via Greater Hamilton Tourism.
May weather in Hamilton, Ontario is unpredictable — temperatures typically range 12–25°C with possible rain that affects trail conditions
Overnight temperatures can drop significantly during the night loops — layers required for all 100M runners
No required gear specified
No recommended gear specified


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