Run The Grim Reaper 2027
The Grim Reaper, Grimsthorpe Castle

Grimsthorpe Castle · 22 & 23 May 2027

Run The Grim Reaper 2027

Four solo distances, a 100-mile relay and a night 10 on a stunning castle estate in South Lincolnshire. All abilities, a friendly vibe, and a 4.9-star rating from the people who have run it.

When
Sat 22 & Sun 23 May 2027
Where
Grimsthorpe Castle, Bourne
Distances
10 · 40 · 70 · 100 miles · Relay
Organised by
Bog Dog Running, Stamford

4.9

On Let's Do This

320+

Runners in 2025

10mi

The loop

550ft

Climb per lap

6

Ways to race it

Choose your distance

One loop. Six ways to run it.

Every race runs the same 10-mile loop around the Grimsthorpe estate. Pick the distance that suits you, from a first trail 10 to the full 100.

Dogs welcome

10miles

Solo · 1 lap · Day

Start
Sat 10am
Age
16+
£35
Book
Night race

10miles

Solo · 1 lap · Night

Start
Sat 9pm
Kit
Head or chest torch
£35
Book
First ultra?

40miles

Solo · 4 laps

Start
Sat 8am
Cut-off
27 hours
Age
18+
£90
Book

70miles

Solo · 7 laps

Start
Sat 7am
Cut-off
28 hours
Pacers
From mile 50
£140
Book
The big one

100miles

Solo · 10 laps

Start
Sat 7am
Cut-off
28 hours
Pacers
From mile 50
£160
Book
Bring the club

100mile relay

Teams of up to 5 · 10 laps

Start
Sat (see briefing)
Cut-off
28 hours
After 6pm
Torch required
£300per team
Book

All finishers receive a medal. Trophies for first, second and third male and female in every solo race, and for the winning relay team. You can't change distance after entering, and dropping down mid-race counts as a DNF.

The Grim Reaper course at Grimsthorpe Castle 10-mile loop · 550ft per lap

The course

One loop around a castle estate

The route is a 10-mile loop that covers beautiful grass trails through ancient woodland, limestone tracks, quiet estate roads and a stretch along a disused Victorian railway line. It skirts the estate lake before reaching the start and finish in front of the castle itself.

It's undulating with no major hills, which makes it ideal for a first ultra, a step up in distance or a PB attempt. The course is fully marked.

Terrain
Estate roads, limestone tracks, grass trail. Trail shoes recommended.
Elevation
550ft per lap. Undulating, no major hills.
Aid station
Mile 5: water, limited snacks, toilet. Cupless race.
Start / finish
In front of the castle. Hot food and drinks 8am to 2pm Sat.
Camping
On site Friday and Saturday nights, next to the start.
Medics
Fully qualified medics on site throughout.
The Grim Reaper course at Grimsthorpe Castle

The new Grim Reaper

Built by runners, for every runner

The Grim Reaper was relaunched in 2023 by Steve Cole and Laura Bailey, runners local to the Grimsthorpe Estate. Their plan was simple: an event that caters for runners of all abilities, in a stunning location, with a friendly, supportive vibe.

Judging by the 4.9 out of 5 rating from the 320+ runners who took it on in 2025, it's working. Bog Dog Running, Stamford's specialist running shop, is behind the event, so there's a well-stocked running shop on site should you forget anything.

Need to know

Everything before the start line

Kit, rules, cut-offs and the small print. Read it once now so race weekend is all about the running.

Start times and location

Grimsthorpe Castle, Bourne, PE10 0LY · grimsthorpe.co.uk

Saturday 22 May 2027

  • 100 and 70 miles: 7am
  • 40 miles: 8am
  • 10-mile day: 10am
  • 10-mile night: 9pm

The 70 and 100-mile races have a strict cut-off of 28 hours. The 40-mile race has a strict cut-off of 27 hours.

Mandatory kit

40, 70 and 100-mile solo races

Mandatory kit applies from 6pm. Before 6pm you are free to carry what you want. Everyone starting a lap after 6pm MUST be carrying all mandatory kit, and we will be checking anyone we feel isn't carrying the right gear.

  • Fully charged mobile phone with the numbers for the Race Medic and Race Directors
  • Survival blanket (1.4m x 2m minimum)
  • Head torch or primary light source, minimum 75 lumens
  • Back-up light source
  • Long-sleeved baselayer, separate to what you start in
  • Waterproof jacket
  • Water bladder, vest or bottle carrying a minimum of 1 litre

10-mile night and relay runners after 6pm

  • Head torch or chest torch

There will be a well-stocked running shop on site should you forget anything.

Cupless race: bring your own cup. Cups will be available to buy on the day.

Aid station, food and medics

Ultra-distance runners are expected to be self-sufficient and manage their own supplies. You are welcome to bring a tent or shelter to set up near the start and finish.

There is an aid station at mile 5 stocked with limited snacks and water, with a toilet alongside it.

Hot food and hot and cold drinks are available to buy at the start and finish from 8am until 2pm on Saturday.

Fully qualified medics are on site throughout the event.

Pacers, crew and spectators

Pacers (70 and 100 miles only)

Permitted from mile 50, on foot only, one pacer per runner at any one time. Runners are responsible for the actions of their pacers.

Crew

You are welcome to walk the whole course, but a crew point is only permitted at the start and finish. Anyone found breaking this rule will be disqualified.

Spectators

Entry to the estate is £5 per adult and £2.50 per child, 100% of which goes to the Grimsthorpe & Drummond Castle Trust Limited (registered charity 507478). Walk the whole course to cheer runners on, grab food and drink, and the adventure playground will be open.

Camping

Runners are permitted to camp on site on the Friday and Saturday nights. The camp area is close to the start and finish line, making it ideal for storing supplies for the race.

Strictly no fires or BBQs.

Race rules
  • Follow the marked course at all times. Cutting the course means instant disqualification.
  • Bib numbers on the front of your shirt or shorts, visible at all times.
  • No stashing food or supplies on the course.
  • Littering means instant disqualification, and that includes the car park after the event. Respect the outdoors and the time and cost of clearing YOUR rubbish.
  • Carry mandatory kit at all times once it applies.
  • Comply with all instructions given at the race briefing.
  • If you can't finish, you MUST inform the race directors.
  • Walking poles are permitted.
  • Dogs are welcome in the 10-mile solo races only. This is not a canicross event: start at the back, be comfortable not racing, and keep dogs on a lead as there is livestock on the estate.
  • 10-mile races: no under 16s. Ultra distances: no under 18s.
Are you ready? Suggested experience

There's no official qualification standard, but we suggest:

  • 40 miles: comfortable running 15 to 20 miles.
  • 70 miles: comfortable with marathon to 50km distances.
  • 100 miles: you have completed 50+ miles within the last year with a finish of at least 13 hours.

Not sure? Pop into the shop in Stamford and talk it through with us.

Withdrawals, deferrals and transfers

If you need to withdraw for any reason we are unable to offer a refund. You can defer your place to 2028 up to four weeks before the race (23 April 2027). After this our race-day costs, which are based on numbers, have been incurred.

You can also transfer your place to another runner: email hello@bogdogrunning.co.uk with their details. Transfers after 26 April incur a £5 admin fee.

Should the 2028 event not go ahead due to unforeseen circumstances, your deferral is void and no refunds will be given.

You cannot change the distance you selected on entry. Enter the 100 and stop at 70 and you're a DNF; enter the 70, finish and feel good, and you can't upgrade to the 100.

Event disclaimer and terms

I accept the following terms for my own entry. I also accept the terms on behalf of any other participants I am entering in this event, all of whom have been provided with a copy of these terms and accept them: I declare that the information I give is complete and correct. I understand and agree that I participate in this event at my own risk and that I must rely on my own ability in dealing with all hazards. I am aware that the function of the marshals is only to indicate direction and that I must decide if the movement is safe. I agree that no liability whatsoever shall be attached to the promoter, promoting club, meeting sponsor(s) or member of the promoting club in respect of any injury, loss or damage suffered by me on or by reason of the event, however caused. I consent to publication of my name, club, race category, race number, finishing time and race position in race pre-entry and results lists.

Grim Reaper kit