La Diagonale des Yvelines (La Diag 78)
Location: Rochefort-en-Yvelines
Distances: up to 105 km
Elevation gain: up to 1,500 m
Month: April
⭐ “It’s truly a race where you experience so much, thanks to both the organisation and the incredibly dedicated volunteers supporting every runner.”
⭐ “From the very start, the warm welcome almost makes you forget you’re about to voluntarily punish your quads.”
⭐ “Precise course marking — impossible to get lost. Generous and delicious aid stations. A festive and energetic atmosphere.”
⭐ “A trail just the way I like it — enjoying beautiful nature while pushing yourself.”
⭐ “A truly beautiful race… MAGNIFICENT, pure happiness.”
⭐ “Excellent organisation (parking, shuttle buses, briefings…), with outstanding volunteers all along the course.”
⭐ “What an atmosphere thanks to the volunteers and supporters!! I was genuinely moved many times when passing them.”
⭐ “An amazing race from start to finish… everything was absolutely perfect.”
Race description
La Diagonale des Yvelines offers a unique north-to-south crossing of the Yvelines region, in the heart of an exceptional natural environment just outside Paris.
With 5 race formats and starts from several iconic locations (Breuil-Bois-Robert, Château de Béhoust, Étangs de Hollande, Rochefort-en-Yvelines), all routes converge towards a single finish line in Rochefort-en-Yvelines.
Between deep forests, technical trails, preserved landscapes and local heritage, Diag 78 delivers a true immersion in nature — just a few kilometres from the capital.
Why it’s a must-run race
La Diagonale des Yvelines stands out for:
- a true nature trail near Paris, rare so close to the city
• an immersive and scenic experience less than 40 km from the capital
• a high-quality organisation (course marking, logistics, aid stations)
• a unique atmosphere driven by passionate volunteers
• a human-scale event, allowing real proximity with runners
• a wide range of distances, accessible to all levels
A race that perfectly captures the spirit of trail running: authenticity, community, and connection with nature — without having to travel far.