Tackle one of France's most legendary and venerable ultra-marathons at the 100 km de Steenwerck, a monumental challenge taking place from May 13 to 14, 2026. Since its founding in 1976, this iconic event has stood as a true test of endurance, attracting walkers, runners, and ultra-athletes from across Europe to the flat but demanding roads and country lanes of French Flanders. The race is a unique 24-hour journey, where participants push through the day and into the night, covering the classic 100-kilometer distance while being supported by enthusiastic local volunteers and communities along the route. More than just a race, it is a deep-rooted local tradition and a celebration of human resilience, fostering an incredible spirit of camaraderie among competitors who share this profound physical and mental challenge. The organization, honed over nearly five decades, is renowned for its impeccable support, with well-stocked aid stations, medical teams, and a festive atmosphere that carries you from the start in Steenwerck to the triumphant finish line. Whether you are a seasoned ultra-runner aiming for a fast time or a determined walker seeking to complete the distance within the generous time limit, the event offers an accessible yet utterly demanding goal. Toeing the start line of the 100 km de Steenwerck means becoming part of a rich history and joining a community bound by the simple, powerful act of covering 100 kilometers on foot.
Races Offered
100 km course
May 13, 2026
straighten
Distance —
100K
terrain
Type ——
timer
05:00
100 km open
May 13, 2026
straighten
Distance —
100K
terrain
Type ——
timer
19:00
Weather Overview
These values represent the 3-year monthly averages for May in Steenwerck.
Temp (°C)
Feels Like (°C)
thermostat9.2° / 18.2°
wb_sunny6.8° / 15.7°
Wind (km/h)
Humidity (%)
air12.3 /
water_drop77.3%
Temp (°C)
Feels Like (°C)
Wind (km/h)
Humidity (%)
thermostat9.2° / 18.2°
wb_sunny6.8° / 15.7°
air12.3 km/h
water_drop77.3%
About Steenwerck
Learn more about the host city, Steenwerck.
Steenwerck is a commune, in French Flanders, in the Nord department in northern France. It is located about 25 km (16 mi) north of Lille. People from Steenwerck are known as Steenwerckois.