Hundred Hills 50km, live.

Centurion's season opener at Stonor Park

The Hundred Hills 50km is a trail ultra through the Chiltern countryside that opens Centurion Running's season, starting and finishing at Stonor Park.

The 2027 edition is on Saturday 20 March 2027. Registration, start, finish and race HQ are at Stonor Park, Stonor, near Henley-on-Thames, which the organiser describes as 850 years old. The race starts in two waves, at 08:45 and 09:00, set by each runner's estimated finish time, and only runners in wave 1 are eligible for the overall awards.

The course is made of two different 25 km loops with about 4,000 ft (1,200 m) of climb, roughly 80% trail and 20% road. It visits villages and ancient woodland, is marked with Centurion ribbons and arrows for its whole length, and has five aid stations.

With a 9 hour cut-off, the organiser pitches it as a race for people taking on their first ultra, and up to 600 people start. Pacers and crews are not permitted. Mandatory kit includes a charged mobile phone, bottles or a bladder for at least 1 litre of water and a survival blanket, and trail shoes are advised. Hot food and drink at the finish are included in the entry fee.

Parking is at the start and finish, so bags are best left in cars. Participants who arrive without a vehicle can hand a finish line bag in at registration.

Livebib lets family and friends follow a participant live if that person chooses to share the position of the phone they carry. It is not the organiser's timing system, and official results always come from the organiser.