Runaway Racing

Race details

Next edition - 26th April 2025

A 100K ultra marathon along the best and most loved trails within the Chiltern Hills.

Our debut 100K ultra marathon will take place on 26th April 2025 on a route that combines the most loved trails and landmarks within the central Chiltern Hills.

The route starts and finishes in Chesham with runners completing an anticlockwise loop passing many landmarks along the way, including Ashridge Esate, Ivinghoe Beacon, Coombe Hill & Bledlow Ridge.

Enter event

100K Ultra

£120/118 (UKA Affiliated)


Key Information

Saturday 26th April 2025
Start Time
Time allowed
18 hours
100K / 1800m+
Event Base
Chesham Guides HQ, Buckinghamshire, HP5 1HX
GPS Tracking
Max Runners
Minimum Age
UTMB Index
UTMB World Series Index Race
TRA Permit No. TBC.
Race held under UKA rules.

Route Map

Event Downloads

Last updated - February 2024 - Route uploaded

Info document
A downloadable PDF with all key race information.
GPX File
A raw GPX track of the route.
OS Maps
Route trace via Ordnance survey maps, subscription required to view OS map layer.
Route via Garmin Connect.
Google Maps
Interactive route viewable using the Google Maps app
Printable Map
An A4 map of the route to print at home.

Route Description

The route starts in Chesham and follows an anticlockwise loop along some of our favorite trails in the Chilterns.

The first leg to CP1 (15K) follows the Chiltern Link trail and heads east to Hastoe. From this first checkpoint, runners complete a loop around National Trust's Ashridge Estate, via Little Gaddesden (CP2), which includes a stunning section of The Ridgeway from Ivinghoe Beacon to Aldbury.

Once back at Hastoe (CP3 - 44k), runners will have access to their drop bag before continuing along The Ridgeway, passing through Tring Park, Wendover, Coombe Hill, Whiteleaf Hill (CP4 - 60K), and along to Bledlow Ridge.

The Bledlow Ridge Village Hall checkpoint marks 75K into the race; the final leg follows a selection of woodland trails through Hampden and along to Great Missenden.

From Missenden, the end is in sight as the loop is complete, and you arrive back in Chesham.


Hastoe Village Hall
Little Gaddesden Village Hall
Hastoe Village Hall
The Plough at Cadsden
Bledlow Ridge Village Hall
Great Hampden

Keep scrolling for more event info

Race Navigation
Race checkpoints

Aid stations

There are six checkpoints on the route, at 15km, 29km, 44km, 60km, 75km, 85km. All checkpoints will contain the following items.

  • Water
  • Coke
  • Precision Fuel & Hydration - PH 1000 Electrolyte Drink (pre-mixed)
  • Precision Fuel & Hydration - PF 30 Gels
  • Precision Fuel & Hydration - PF 30 Chews
  • Selection of crisps and sweets
  • Pre-made sandwiches (jam, peanut butter, cheese)
  • Chia Charge Mini Flapjacks
  • Selection of Fresh fruit (banana, orange, watermelon)
  • Hot drinks/water available 44k, 60k & 75k
Event base

Event base

The event is hosted at Chesham Guides Headquarters, based in Lowndes Park in Chesham.

The guide hut has direct access to the trail and is an ideal location for the start/finish.

Post-race food will be available to all runners.

View on Google Maps

Required Gear

Required gear

All runners will be required to carry the following items for the entirety of the run:

  • Mobile phone (emergency number saved)
  • Route GPX on watch/phone + paper map (provided)
  • Waterproof/windproof jacket
  • Waterproof trousers
  • Additional long sleeve layer (to be kept dry for emergencies)
  • Hat or buff
  • Reusable soft cup
  • Basic first aid supplies (plasters/tape/bandage/foil blanket)
  • Headtorch + spare battery
  • Refillable water/hydration system (0.5L min)
  • Bag/vest to put everything in
  • Race nutrition
  • Cash or bank card

Entry details

Registration is £120 (or £118 to affiliated runners). The first 25 runners will recieve a 10% discount. Runners must be aged 20 years or older.

  • Entry to the 100K race
  • Event permitted by the TRA/UKA
  • Finishers medal
  • GPS Tracking
  • Chip timing with live results
  • Medical support
  • Marked/marshalled route
  • Drop bag at Hastoe CP.
  • Event photos
  • Post race meal

Entry details

Withdrawal options

By entering our race, you agree to the following withdrawal policy. This policy applies to all runners with the exception of women of cannot compete due to pregnancy.

Withdrawal date
Credits issued
More than 4 weeks before race day

*Entrants to The Ridgeway Challenge are entitled to defer their entry for up to 2 years, or receive a 90% entry voucher to use on any Runaway Racing event.

Credits can be used on future race entries, any time during the following 2 years.

Withdrawal requests must be completed online via our manage booking functionality.

Manage Booking
Event withdrawal

It was so well organised both in the weeks building up to it and on the day, and the course was so well marked you couldn’t possibly go wrong out there.


Chiltern Ridge 50km, 2021

Loved this! Course was beautiful and very well signposted. Friendly and really helpful marshals. Aid stations well stocked. Very well organised- would definitely do again.


Chiltern Ridge 50km, 2023

Event partners

National Trust
The Ridgeway National Trail
Precision Fuel & Hydration
Chiltern Society
Ugoku Projects
UTMB World Series
Trail Running Association
Runaway Racing Trig Point Illustration

Our trail running races

Dunstable Downs Half Marathon Sold out 21.2km - 14th July 2024
Suffolk Coastal Path 50K 50km - 14th September 2024
North Chilterns 50K 50km - 13th October 2024
Chiltern Ridge Winter 50K 50km - 16th November 2024
Chiltern Hills Invitational 10km - 8th December 2024
Chiltern Ridge Ultra 50K 50km - 5th April 2025
Chiltern Hills 100K 100k - 26th April 2025
The Ridgeway Challenge 86-miles / 139km - 31st May 2025
Tewinbury Trail 10K 10km - 8th June 2025
Chiltern Ridge Half Marathon 21.2km - 6th July 2025
Hughenden Manor Half Marathon Half Marathon - 19th July 2025
Hughenden Manor 10K 10K - 19th July 2025
Greensand Country 50K 50km - TBC

Past results & photos

Not sure which race to choose, check out our past event results and photos.

Results & photos