Centurion Hundred Hills 50km

Centurion Running’s Hundred Hills 50km is a scenic trail ultramarathon through the Chiltern countryside, starting and finishing at Stonor Park near Henley-on-Thames. The race covers two 25km loops for a total of 50km, with about 4000 ft (1200 m) of elevation gain and a 9-hour cut-off. The route is 80% trail and 20% road, winding through ancient woodland and picturesque villages.

The event, a season opener for 2026, offers full on-course marking, five well-stocked aid stations, medical support, and a spectator-friendly finish with on-site food and drink. Finisher medals (with a tree-planting option) and age-group prizes add to the appeal. Visit the organization's website for the most recent information.