2 people running outside up a hill in Macmillan t-shirts.

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Run The Trail

Take on Run the Trail, an exciting new trail running challenge in Cassiobury Park, Watford on 20 September 2026. Leave the pavements behind, challenge yourself in beautiful surroundings and make every step count by supporting people living with cancer.

New

Date

20 September 2026

Location

Cassiobury Park, Watford

Join

Early bird offer £5 registration fee / £200 fundraising pledge.

Distance

5K and 10K

About the event

This trail running event takes you across varied terrain, from parkland paths to scenic stretches of woodland trails crossing the Grand Union Canal and the River Gade. Choose between the 5km or 10km route and take on a challenge that suits you, all within an easily accessible location.

Run at your own pace and be part of a supportive community coming together on the trails to do whatever it takes to support people living with cancer.

Please make sure you have read our Terms and Conditions before signing up.

The Run The Trail experience

We’ll support you from the moment you sign up to the moment you cross the finish line.

Free Macmillan running top
Clearly marked route
Medical assistance
Run the Trail medal
Regular e-newsletters to keep you up to date

Run the trail runner with medal at finish.

"You don't have to go fast, you just have to go."

Woman in orange vest out for a run in a park.

After completing chemotherapy and radiotherapy treatments for breast cancer, Michelle knew she needed some guidance to help build her fitness again.

Read Michelle's story

How your money helps

Donations make up 98% of our annual income so we simply couldn’t do what we do without you. By pledging to raise at least £200 when you take part in Run the Trail, you will be helping to fund our vital services to help people living with cancer.

Ready To Join

By joining us you'll know that you're helping improve the lives of people living with cancer in the UK today.

Event Accessibility

Guide and support dogs are welcome at this event.

For participants who need a guide to make this event accessible to them your guide can accompany you free of charge, but they must register for the event. Please email running@macmillan.org.uk to let us know and we will provide a discount code to waive their registration fee.

Due to the nature of this event it is not accessible for wheelchairs.

If you have any questions about whether this event would be suitable depending on your needs, please get in touch and we will be happy to see how we can accommodate you.

Volunteering

We need the enthusiasm and experience of our volunteers to make this event special. If you would like to help us deliver this event then we would love to hear from you. Please email the volunteering team to express your interest and we can discuss how you can support on the day.

Run the Trail - Frequently Asked Questions

Got a question about taking part? Most questions can be answered by the event FAQs. Otherwise you can also get in touch with the Macmillan team by calling 0300 1000 200 or emailing running@macmillan.org.uk.

Before the event

What is the address for the event venue?

The event will take place at The Bandstand, Cassiobury Park, Watford, WD18 7HY.
Is there parking at the venue?

Cassiobury Park has limited parking at the main car park off Gade Avenue (WD18 7LG), which is free for the first 2 hours and then paid via Pay & Display or RingGo. Other options include nearby council car parks. There is no reserved parking for this event.
How much is entry to the event?

Entry to the event is £10, which will cover some of the cost of your place. We also ask for a sponsorship pledge of £200, but encourage you to raise as much as you can to support people living with cancer. The entry fee is non-transferrable and non-refundable.
Will I get sent a Macmillan running top?

Yes, you will receive a Macmillan running top in the size you request on the registration form. This will be sent to you within two weeks of registering for the event.
Can I transfer my place to another person?

Places are non-transferrable. Everyone must register directly using the registration form so that we have the correct details and permissions.
When does registration to the event close?

Registration will close two weeks before the event or once event capacity has been reached, whichever comes first.
What if I become injured or need to cancel my place?

If you are injured or need to cancel your place, please email running@macmillan.org.uk or call 0300 1000 200.
What if I want to change the trail distance I want to run?

No problem at all. Please email running@macmillan.org.uk or call 0300 1000 200.
When will I receive my official race day information?

You will receive this information approximately four weeks before the event.
Do I have to run? Can I walk a trail?

The event is set up for runners, but if you need to walk some parts of the route that is absolutely fine. Marshals will be on the route so no one will be left behind.
What is the minimum age limit?

Participants must be aged 17 or over on the day of the event. Entrants under 18 will require parental or legal guardian consent, and insurance must be arranged by the parent or guardian.
Can dogs come and watch?

Yes, but for safety reasons we advise not bringing pets into the park for this Challenge Event. Any dogs must be kept on a lead at all times and remain the responsibility of their owners.

Fundraising

Is there a fundraising target?

We ask all participants to raise as much as they can to support people living with cancer, with a minimum pledge of £200.
How do I set up my fundraising page?

You can set up a personalised JustGiving page using this link. Share it with friends, family and colleagues and donations will be sent directly to Macmillan.
When do I have to reach my £200 fundraising pledge?

Within four weeks of completing the challenge. We recommend starting fundraising as early as possible.
If I sign up with a team, does each team member have to raise the minimum fundraising pledge?

Yes, the minimum fundraising pledge is £200 per person.

At the event

Will there be a bag drop at the event?

Yes, details will be shared closer to the event date.
Will there be toilet facilities?

Yes, toilets will be available within the event village.
Can my family and friends come to support me?

Yes, absolutely. Details on access to the route will be shared closer to the event date.
What happens if I fall ill or get injured on the event?

Marshals and mobile medics will be on hand to support you if you become unwell or injured.
Is this event timed?

Yes, this event will be timed and each participant will have a timing chip.
How can I contact you?

Email running@macmillan.org.uk or call us 9am–5pm on 0300 1000 200.