The Chiltern Ridge Winter 50K Ultra Trail is a 50 km trail ultra in the Chilterns, run between Berkhamsted and Wendover. It is the main event from Runaway Racing, a small Wendover-based organiser focused on trail half marathons and 50K events. The race carries a UTMB Index category, providing runners with an indexed result for mountain and trail racing profiles.
Runners start inside the grounds of Berkhamsted Castle, then head toward Wendover through the Ashridge Estate and along the Ridgeway. The route climbs close to 1,000 metres, making it a hilly off-road 50K rather than a flat speed test. Recent results show just over 300 finishers, with front runners finishing under four hours and the first woman a little under five hours, attracting both competitive trail runners and regular ultra runners seeking a demanding Chilterns course.