Chiltern Hills 100K Ultra Marathon

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Race details

Next edition - 2nd October 2027

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

The Chiltern Hills 100K will return October 2nd, 2027.

Our route follows an awesome anticlockwise loop passing many of the Chilterns best landmarks - including the Ashridge Estate, Coombe Hill, Whiteleaf, Bledlow Ridge, Great Hampden and much more.

It's truly the best way to discover what the Chilterns has to offer, all in one day!

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Chiltern Hills 100K

£142 (£140 UKA Affiliated)

Entries are now open!

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Price tiers

£142/£140

First 50 entries

▶ Active

£152/£150

Entries 51-99

£162/£160

Entries 100+

Enter now and save £20 vs the final price

Key Information

Race info

Date

Saturday 2nd October 2027

Start Time

07:00

Time allowed

19 hours

Distance/Elevation

100K / 1800m+

Event Base

Chesham Guides HQ, Buckinghamshire, HP5 1HX

Navigation

Fully Marked

GPS Tracking

Yes - Open Tracking

Max Runners

250

Minimum Age

UTMB Index

Licence

Licensed by the Trail Running Association. Race held under UKA rules.

Male Course Record

Mike Stainthorpe
09:22:52 (2025)

Female Course Record

Molly Burlingham
11:24:18 (2025)

Route Map

Explore the route and elevation profile below, or download the route for your watch, OS Maps, Garmin and more.

Download the route

Route Description

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

Image Highlights

Videos

Event Downloads

Last updated - Dec 2026

Runner's Guide

A downloadable PDF with all key race information.

Coming soon

Spectator Guide

A helpful list of places for spectators to see the runners.

View

GPX File

A raw GPX track of the route.

Download

Route via Ordnance Survey maps

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Download the route to your Garmin device

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View the route on Strava

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Interactive route via Google Maps

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Printable Map

An PDF version of the race route

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Checkpoints

Where each checkpoint is, how far into the route, and what to expect when you get there.

Start

Start Chesham Guides HQ, Bury Lane, HP5 1HX Google Maps

Start time
07:00
Distance
100k
Time limit
19 hours

Bib collection: Race morning only, 05:30–06:30
14km

CP1 - Hastoe Village Hall 14km · Cut-off n/a

Hastoe Village Hall

Into route
14km

To next CP
14km

To finish
86km

First runner
08:10

Cut-off
n/a

Toilet
Yes

Crew & spectators: No – Crews are not permitted at this location.
28km

CP2 - Little Gaddesden Village Hall 28KM · Cut-off n/a

Little Gaddesden Village Hall

Into route
28KM

To next CP
13.4km

To finish
72km

First runner
09:25

Cut-off
n/a

Toilet
Yes

Crew & spectators: No – Crews are not permitted at this location.
41.4km

CP3 - Hastoe Village Hall 41.4KM · Cut-off 14:30

Hastoe Village Hall

Into route
41.4KM

To next CP
16.4km

To finish
58.6km

First runner
10:30

Cut-off
14:30

Toilet
Yes

Crew & spectators: No – Crews are not permitted at this location.

Your on-route drop bag will be available here.
57.8km

CP4 - Whiteleaf Hill 57.8KM · Cut-off 18:00

Whiteleaf Hill

Into route
57.8KM

To next CP
17.5km

To finish
42.2km

First runner
12:00

Cut-off
18:00

Toilet
No

Crew & spectators: Yes - Crews are permitted at this location
75.3km

CP5 - Bledlow Ridge Village Hall 75.3KM · Cut-off 21:15

Bledlow Ridge Village Hall

Into route
75.3KM

To next CP
12.7km

To finish
24.7km

First runner
13:30

Cut-off
21:15

Toilet
Yes

Crew & spectators: Yes - Crews are permitted at this location
88km

CP6 - Little Hampden 88KM · Cut-off 23:30

Little Hampden

Into route
88KM

To next CP
n/a

To finish
12km

First runner
14:30

Cut-off
23:30

Toilet
Yes

Crew & spectators: No – Crews are not permitted at this location.
Finish

Finish Chesham Guides HQ, Bury Lane, HP5 1HX Google Maps

Distance
100k
Time limit
19 hours
Course closes
Sunday 02:00

What's at each checkpoint

There are six checkpoints along the race route. All checkpoints will contain the following items.

Drinks

Water
Coke
Precision Fuel & Hydration - PH 1000 Electrolyte Drink (pre-mixed)
Hot drinks/water available 44k, 60k & 75k

Fuel

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)

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

Mandatory Kit

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
Refillable water/hydration system (0.5L min)
Waterproof or windproof jacket
Additional long sleeve layer (to be kept dry for emergencies)
Additional full leg cover (to be kept dry for emergencies)
Head torch + spare battery
Warm hat/buff & gloves
Reusable cup
Basic first aid supplies (plasters/tape/bandage/foil blanket)
Bag/vest/belt to put everything in
£20 cash or bank card
Race nutrition

Entry details

Entry is open to all runners aged 20 years or older, there are no qualifying requirements. Your entry includes:

Entry to the 100K race
Event licensed by the TRA
Finishers medal & t-shirt
GPS Tracking
Chip timing with live results
Medical support
Marked/marshalled route
Drop bag at Hastoe checkpoint
Event photos

Event FAQs

We've answered some common questions below. Please contact us if you have any further queries.

How difficult is this race?

The Chiltern Hills 100K is a challenging ultra, with around 1,800m of climbing on hilly, often muddy trails. Most runners use a run/walk strategy, hiking the climbs and running the flats and descents.

The generous time limit means it's well suited to runners stepping up to their first 100K, providing you have some ultra or long-distance experience behind you.

Do I need to qualify?

No, there are no qualifying standards required to enter this race. Entry is open to all runners aged 20 or over on race day.

What are the cut-off times?

There is an overall 19-hour time limit for the race. Checkpoint cut-offs will also be enforced, and you must leave each checkpoint by the time stated to be allowed to continue. Full details of the checkpoint cut-offs will be published in the runner's guide ahead of race day.

I'm worried about getting lost?

The route is fully marked with our orange arrows and ribbons, and marshalled at key locations.

All runners must also carry the route GPX on their watch or phone as a backup.

How many checkpoints are there and what do they provide?

There are six checkpoints on the route: Hastoe (14km), Little Gaddesden (28km), Hastoe (41.4km), Whiteleaf Hill (57.8km), Bledlow Ridge (75.3km) and Little Hampden (88km).

All checkpoints stock water, Coke, Precision Fuel & Hydration electrolyte drink, gels and chews, sandwiches, flapjacks, fruit, crisps and sweets. Hot water is also available at all locations.

Can I have a drop bag?

Yes, you may drop off two bags at the start on race morning. One on-route bag (max 30 litres) will be transported to CP3 at Hastoe (41.4km) and then returned to the finish. A second finish line bag (max 60 litres) will be kept safe and returned to you at the finish. Please label both bags clearly with your name or race number.

Are crews allowed at this race?

Yes, crews are welcome. Crews may meet runners at CP4 (Whiteleaf Hill, 57.8km) and CP5 (Bledlow Ridge, 75.3km), but are not permitted at CP1, CP2, CP3 or CP6 due to limited parking and to reduce disruption to local residents.

Crews may also meet runners at any other point along the route. Please see our spectator & crew guide for suggested crew access points.

What mandatory kit do I need?

You must carry a full set of mandatory kit at all times, including a head torch and spare battery, waterproof jacket, spare warm layers and basic first aid supplies. The full list can be found in the kit section above.

You will be asked to show two items of mandatory kit at registration, and time penalties will be applied to anyone found without the correct gear.

When and where is registration?

Registration takes place on race morning only, between 05:30 and 06:30, at the event base (Chesham Guides HQ, Bury Lane, HP5 1HX). You will collect your race number and have your GPS tracker attached to your running pack.

Where can I park?

There is no parking at the event base, so all runners and spectators must arrive on foot. We recommend the Water Meadow Car Park (HP5 1LF, a 350m walk) or Albany Place Car Park (HP5 1EP, a 650m walk) for all-day parking.

How can I attend this event without a car?

Chesham station is at the end of the Metropolitan line, with direct services from central London, and is a short walk from the event base in Lowndes Park.

Where can toilets be found at this event?

There are toilets at the event base and at every checkpoint, with the exception of CP4 at Whiteleaf Hill.

What happens if I drop out mid race?

If you decide not to continue, this must be done at one of the checkpoint locations, unless there is a medical reason that prevents you from doing so. Please let the checkpoint team know you are withdrawing.

In the event of a DNF, it is your responsibility to return your GPS tracker and collect your drop bags. Trackers that are not returned cost £120 to replace.

How can friends and family follow my progress?

All runners carry a GPS tracker, which broadcasts their location for the full duration of the race, and there is chip timing with live results. Spectators are also welcome at the start and finish in Chesham.

Is this a UTMB Index race?

Yes, the Chiltern Hills 100K is a UTMB World Series Index race in the 100K category. The race is also licensed by the Trail Running Association and held under UKA rules.

How do I follow the route using my phone or watch?

Most GPS watches allow you to upload a GPX file of the route for you to follow whilst running. Typically this is done by loading the route GPX file into the app (i.e Garmin Connect), and then syncing your phone/watch together.

If you don't have a GPS watch we would recommend using OS Maps (£20/year) or Strava Premium (£48/year).

What are the course records?

The men's course record is 09:22:52, set by Mike Stainthorpe in 2025. The women's course record is 11:24:18, set by Molly Burlingham in 2025.

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

90%

Credits are only redeemable once, and can be used on future race entries, any time during the following 12 months.

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

Manage Booking

Previous editions

2026 Chiltern Hills 100K Results Photos

2025 Chiltern Hills 100K Results Photos

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.

Darren

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.