Pilgrim Challenge 2025 now open for booking!

All 2024 events open for booking!

No. of days 1 day

Distance 31 / 16 mi

Ascent gain 979 / 558 m

Accom. no

Food no

Set in the picture-perfect Chilterns, the Chiltern Challenge helps fund life-changing operations for children in developing countries and is the ideal 50km introduction to ultra marathon running. Escape to the Chilterns, an area of outstanding natural beauty. What's more, it's FREE to run, if you commit to raising funds for Humanity Direct.

New this year you have the option of the full 50km ultra marathon, a 25km half ultra or run the full ultra as part of a team of up to 5 people!

If you choose to take part as a team you will be given one race number and timing chip that your team will need to get from the start to the finish. It's up to you which part of the course each team member will cover (each person can run more than one leg) but note that you can only hand over at the standard ultra checkpoints and also that it is your responsibility to transport your team members to their handover points. 

You will enter on behalf of your team and we'll ask you for the names and other basic information of your fellow team members. You can make changes to your team up until close to the event. Our usual cancellation/deferral rules apply but requesting either will be on behalf of your entire team.

Latest results

We are delighted to support SheRACES and commit to providing a great experience for female participants. Find out more


  • Transport to and from Princes Risborough station
  • Free parking at Princes Risborough School
  • A fully recced and marked route
  • Full medical cover throughout
  • A quality finishers medal
  • Checkpoint food and water at regular intervals
  • Free tea, coffee and cake at the finish
  • Prizes and trophies for overall and category winners
  • A great atmosphere and a fun but challenging day out
  • Action photos en-route, free to download
The winners, runners up and age group winners will receive fantastic prizes or vouchers from our sponsors.


The well-marked circular route will start and finish at Princes Risborough School. Using National Trails and Footpaths, there are clear signposts and post discs, as well as our signs and confidence tape.

We recommend you familiarise yourself with the route before the start of the race and download the GPX file or OS Maps route onto your watch or phone.

Download printable route information.

Showing route for:


#1 Village Green, Dunsmore HP22 6QJ ///rescue.emphasis.overture Grid ref: SP86210521

#2 J/W Ridgeway, Gadmore Lane & Shire Lane, Hastoe HP23 6LU ///riper.divorcing.served Grid ref: SP91390920

#3 Asheridge Farm, Ashotts Lane HP5 2UU ///laptop.pull.billiard Grid ref: SP93000537

#4 Cobblershill Farm, Cobblershill Lane HP16 9PW ///delusions.courts.diverting Grid ref: SP86940365

More info...


CP1, Dunsmore Village Hall HP22 6QJ ///sailor.countries.bench

Great Missenden, Bough's Meadow Link RD HP16 9AL ///boggles.smarting.diets


#1 Village Green, Dunsmore HP22 6QJ ///rescue.emphasis.overture Grid ref: SP86210521

#2 Cobblershill Farm, Cobblershill Lane HP16 9PW ///delusions.courts.diverting Grid ref: SP86940365

More info...


CP1, Dunsmore Village Hall HP22 6QJ ///sailor.countries.bench



Minibus pick up starts from Princes Risborough Station


Registration opens


Walkers mass start


Walker/runners mass start


Runners mass start


25km mass start


Refreshments available


Minibus to the station running all afternoon


Prize giving or when enough runners have finished


Entry for ultra


Entry for half ultra


Entry for team




The entry fee will be donated to fund a vital operation, or alternatively enter for FREE, if you commit to raise funds for Humanity Direct.

If you're fundraising book now through our system, then visit Humanity Direct's website to register yourself.

Please note: a 2.5% service charge, levied by the registration software, will be added to your total. We are using a new entry system that takes payment through the secure system Stripe. No payment information is retained by Extreme Energy, or our entry system tool.

Email us on info@xnrg.co.uk if you have any questions about your options.

If for some reason you are not able to make the event you have entered. The XNRG refund policy is that we will give you 70% refund of your entry fee up to 1 month before the start date of the event. You also have the option (1 month before the date of the event) to get a 100% transfer credit to another one of the other Humanity Direct 1 day events, or you can donate your entry fee to the charity. All entry fee money goes directly to the charity and directly to helping children with life changing operations. These options you can execute on your Ultrabritain entry page.

After this time we are sorry there will be no refunds or transfers to future events. Refunds will be to your booking credit card.

Race-day Preparation

Kit List

The only compulsory kit is a fully charged mobile phone and a minimum 500ml of water, but it's worth taking a look at our recommended kit list.

Other equipment may be made compulsory by the race director depending on the weather.


The event is supported by a Course Manager and a fully qualified medical crew will be in attendance. We strongly recommend taking a moment to read our medical page before booking.


We've answered a range of common questions in our FAQ. For other questions, say hello on info@xnrg.co.uk.


Please watch the Race Director's briefing ready for race day.


Please register and pick up your timing chip from:

More Information

This popular race is especially good for those looking for a supportive event for their first ultra within easy reach of London. And for those wishing to build experience to gain entry to UTMB we can now also offer 2 ITRA points (for full ultra distance only)!

As with all of our events, everything is taken care of at the Chiltern Challenge so you can focus on the experience! We’ll provide transfers from the station, free parking, free photos, changing facilities and heaps of tea and cake.

The XNRG Chiltern Challenge is a unique chance to get a place on an amazing one day ultra for FREE if you fundraise for a Humanity Direct patient, or alternatively donate £65 for the full distance, £38 for the half ultra option or £95 for a team of up to 5 people.

Humanity Direct

In 2019 Humanity Direct raised £24,000 through the three Humanity Direct Ultras, which helped fund life saving and life changing operations for 35 children and we are hoping to raise even more in 2024.

So, how does it work?

It's simple. The entry fee is donated to fund a vital operation or, if you prefer, you can enter for FREE and start a fundraising page instead and raise as much as you can, with a minimum of £65 (£95 for a team).

“The support we’ve had from XNRG has been phenomenal. Thanks to you we’ve rolled out a vital eye-testing programme for children in rural Uganda with over 600 children receiving free glasses so far. Your donations and dedication have also helped us continue to provide life-saving and life-changing surgery for children whose families are live on less than a $1 a day and who would never be able to afford the medical care they need.  XNRG ultras truly do change lives!"

- Nick Swift, Humanity Direct’s Founder


Entries will close one week before the event (or when full). A waitlist option will be available if the event becomes fully booked.

Navigation and Support

Stretching from the River Thames in Oxfordshire to Hitchin in Hertfordshire, the Chiltern Hills are a spectacular Area of Natural Beauty boasting some of the finest protected countryside in the UK.

The well-marked circular route will start and finish at Princes Risborough School (HP27 0DR), incorporating four checkpoints for the full ultra distance, approximately 10km apart, and two at the half ultra.

Using National Trails and Footpaths, there are clear signposts and post discs, as well as our signs and confidence tape. We recommend you familiarise yourself with the route before the start of the race and download the GPX file or OS Maps route onto your watch or phone.

Aid stations

There will be checkpoints at regular intervals with water and food - please bring your own cups. For the full ultra distance there will be four checkpoints and the half ultra will have two.

Due to the risk of cross contamination, we cannot provide checkpoint food to suit all dietary requirements. If you require special food or snacks to suit any allergies or vegetarian/vegan diets, can you please bring your own. Put them in containers, marked with your name and checkpoint number and give them to the checkpoint teams at the start of the race.


Hi, I don't usually respond to organisers after an event. I just wanted to say thanks for organising such an amazing first ultra. The race was superbly organised , well planned , Marshall ands food stops were excellent. I can assure you I will be running in your events again and recommend them to others. Thank you and your team for making the chilterns ultra such a great run.

Hi everybody I would like to congratulate XNRG on a superbly well run event in the Chilterns. It was a fabulous day out in stunning countryside. Everything went like clockwork, registration, briefing and the course was marked perfectly with tape, signs and sometimes quite elaborate pictograms sprayed on the ground making the maps supplied only necessary as an overview of the route. I find it quite mind boggling that you can plot and mark such a varied and interesting course in 31 miles of countryside, check it and then clear up afterwards. It made the entry fee worth it alone.

Just wanted to say thank you to everyone who helped with this event yesterday. It was my first ultra and I absolutely loved it! The fantastic organisation meant all I had to do was concentrate on getting myself round the distance! The malt loaf and coke at the checkpoints were a much needed treat! Thanks again.

We can't wait to see you there! Questions? Say hello on info@xnrg.co.uk

We're proud to partner with...

Join the family

Subscribe to our mailing list and keep informed