Chiltern Hills 100K

Chiltern Hills 100K

The Chiltern Hills 100K is a 100 kilometre trail ultramarathon held on 9 May 2026 with an event base at Chesham Guides Headquarters in Lowndes Park, Chesham, Buckinghamshire (HP5 1HX). The route is an anticlockwise loop of the Chiltern Hills covering around 100K with approximately 1800m of elevation and a maximum field of 250 runners. A time limit of 18 hours applies.

The course passes notable local landmarks including the Ashridge Estate, Coombe Hill, Whiteleaf Hill, Bledlow Ridge, Great Hampden and sections of The Ridgeway, and is fully marked with orange arrows and ribbons. Navigation is supported by open GPS tracking; all runners must carry route GPX on a watch or phone and a printed map provided at registration.

There are six checkpoints and aid stations at approximately 14K, 28K, 41.4K, 57.8K, 75.3K and 88K. Checkpoints provide water, electrolyte drink, gels and chews, snacks, fruit, pre-made sandwiches and limited hot drinks at specified locations. A drop bag service is available at Hastoe.

The event is licensed by the Trail Running Association (license #8208) and is a UTMB World Series index race. Entry is £152 (£150 for affiliated runners) and the minimum age is 20. Required equipment includes a mobile phone with emergency contact, GPX route, minimum 0.5L refillable hydration, waterproof jacket, additional warm layers, head torch with spare battery, basic first aid items, a reusable cup and payment for emergencies. Finishers receive a medal; services include chip timing, medical support, marked route, event photos and a post-race meal. Visit the organization's website for the most recent information.