Trail
42 km (~650 m D+)
42 km
Start: Dec 4, 09:30 PM
Pre-registration: 38.00 EUR

Trail
42 km (~650 m D+)
42 km
Start: Dec 4, 09:30 PM
Pre-registration: 38.00 EUR
Trail
23 km (~350 m D+)
23 km
Start: Dec 4, 09:45 PM
Pre-registration: 23.00 EUR
A forest trail race in the Chevreuse valley (Yvelines) offering two technical routes — 23 km (~350 m D+) and 42 km (~650 m D+) — through forest and heritage sites. Organised by Alternature.
Ravitaillement sur le parcours (eau, produits énergétiques et/ou alimentaires selon les points). Sur place, des boutiques et restauration sont proposés sur les bases de vie.
Pacemakers will run with the field on the 42 km route according to target times displayed on the race-day start corrals (start waves). Pacers carry visible pacer flags to help runners maintain target pace; refer to the published ‘Renntag pour les coureurs’ schedule for exact target times per wave.
Monthly averages based on historical data (2000–present).
23 km (~350 m D+) and 42 km (~650 m D+).
Sunday 6 December 2026.
Start and finish at the mairie du Perray-en-Yvelines (Place de la Mairie), with routes traversing the protected Rambouillet forest and nearby communes.
Online via the official registration page; registration closes 30 November 2026 and closes earlier when quota is reached.
Race number, participant medal, race catering, chip timing, and race organization support.
No race insurance or cancellation coverage is provided.
Last updated: Jun 5, 2026, 11:42:14 PM
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