Distance Kilometres


Ascent Feet


Descent Feet


Number of Runners


By day, Grassholme reservoir boasts magnificent, unspoiled views of the Teesdale Valley in County Durham. Calm, still waters, dotted with anglers, reflect the picturesque rolling pasture. An abundance of wildflowers, Birds of Prey, sheep, cows, wildfowl and roaming deer can be spotted. However, by night, you will observe the ceiling of stars as dusk descends, birds roosting; bats swooping and owls joining in the atmospheric chorus!

There is a fantastic social aspect at Trail Outlaw events, we have a wonderful, friendly community, where everyone is supportive of each other. We host events that encourage personal goals, celebrate successes and recognise the incredible journeys, full of struggles, challenges and determination that lead up to and include the actual trail run. The area is particularly fantastic for campervans, and we have ensured that there is plenty of room to stay over close by the observatory, where you can also deep dive into astronomy, as Grassholme is situated in a protected Dark Skies area. We have chosen to include two distances in this race: 10K and 5K. For those seasoned runners, especially those that enjoyed our Dark Skies runs at Kielder the 10K is a new challenging and exciting trail to choose. We have also introduced a series of 5K runs to encourage, support and include people new to running and/or for those who wish to take part in our events, but find the 10K too far. Take a look at our 5K webpage for more information.

Entry includes:-

  • Bespoke Medal
  • Chip Timing by TOTS
  • Instant Online results by TOTS
  • Feed stations – water and sweets, more substantial snacks and drinks on longer events
  • Fully marked and marshalled route
  • Medical Cover
  • Free event parking
  • First male and female, first in age category. Level up for free!
  • Bespoke memento for all runners
  • Digital photography of event and entrants
  • Chance to purchase bespoke event t-shirt


Book your place now. ENTER NOW

Cut Offs

The race must be completed within 2 hours.

Route and Course Markings

You will follow a circular route, taking you in the first part along the shoreline’s undulating pathway, close to the Pennine Way. Part two includes rougher terrain, following sheep trails, rather than man-made paths - don't worry as they are clearly marked! It is a trail of two tales! You will be supported throughout by our team of incredible marshals, who look after you from start to finish ensuring you have encouragement, fluids and nourishment at each of the checkpoints. Our trails use bespoke timing equipment to ensure accuracy and we have a range of different awards for winning categories.

The course will be marked and flagged and marshals will be on hand at key points in the race. Please remember that navigating the course is your responsibility.

First Aid

The race checkpoint has first aid equipment for minor injuries. The start/finish area will also have first aid provision including a paramedic and an ambulance. Nearest local hospital:- Darlington Memorial Hospital, Hollyhurst Rd, Darlington DL3 6HX. 01325 380100


All finishers get a bespoke medal and a race memento. Free parking for the event and free digital photography. A race t-shirt is also available as an addditional purchase.

There are also male and female prizes for the categories shown below.

Senior 40-49 50-59 60-69 70 plus
First Three First finisher First finisher First finisher First finisher

Race Registration/Parking

Grassholme Reservoir,

Nr Grassholme,


DL12 0PW

Map for Race HQ.

Dark Skies Run @ Grassholme 10K - 13th April 2024

  • 18:00 - 19:30Race HQ

    Opens for race registration, pick up race numbers and race merchandise.
  • 19:55Start/Finish Area

    Race safety briefing
  • 20:00Start/Finish Area

    Race start!
  • 21:00Race HQ

    Awards Presentation
  • 22:00Finish Area

    Race cut off

Dark Skies Run @ Grassholme 10K - Mandatory Kit

  1. Whistle
  2. Head/chest/waist torch
  3. Survival bag for 26.6/Foil Blanket for other races
  4. Hat and gloves
  5. Quality Waterproof jacket
  6. Minimum of 500ml water
  7. Personal cup
  8. Emergency food/sport bar
  9. Fully charged phone

Dark Skies Run @ Grassholme 10K - Rules

  1. All competitors must be running under their own names and numbers. No swapping of numbers or running in another’s place will be accepted. If you are found to be running in another’s place you will be disqualified.
  2. You must log your number with race marshals at each check point. It is your responsibility to make sure the marshal takes your number.
  3. Any competitor who is deemed unfit to continue by the race directors, marshals or medics will be withdrawn from race. The decision will be FINAL.
  4. Runners must carry all mandatory equipment at all times during the race unless stated otherwise at Race Briefing by the Race Director. If found to be not carrying the required kit at any time, you will be disqualified.
  5. If you decide to retire from the race you must notify a marshal. You must surrender your race number and you will not be allowed to continue.
  6. Unsporting behaviour (cheating) will not be tolerated and result in immediate disqualification. This includes but not limited to, not carrying mandatory kit at all times, taking short cuts, use of PEDs.
  7. We strongly advise against the using of NSAIDs (Non-Steroidal Anti-Inflammatory Drugs i.e Ibuprofen) during the events, as they are proven to cause harm during endurance events. Doing so against this advice is strictly at the competitor’s risk.
  8. All runners take full responsibility for their own navigation during the event.
  9. You must have your bib number visible at all times or easily accessible to show the Check Point team.
  10. If you do not leave an aid station before the cut off time you will not be allowed to continue for safety, cut-off times will be strictly enforced. If you get to the finish line after the final cut off you will unfortunately not be listed as an official finisher and will not be eligible for awards.
  11. Littering will result in immediate disqualification. We must respect the trails at all times. Some of our events take place in SSSI (Sites of Special Scientific Interest), and securing permission to host events in these areas is very difficult. If you litter you not only jeopardise the events future, but more importantly you jeopardise the area.
  12. Dogs are NOT allowed to take part in the event. They present a trip hazard to other runners and a risk of upsetting livestock of local land owners.
  13. Dogs are not allowed beyond the safety barrier and main entrance to the camp at Hawkhirst.
  14. You do not have a right of way priority over any other users of the course, you must respect other users of the course throughout the duration of the event.
  15. Earphones/headphones may be used, but MUST be taken off head or out of ears completely at certain points.
    1. When you’re approaching a road crossing
    2. When you’re approaching a checkpoint
    3. If you see a marshal in hi-viz anywhere along the race route
    4. On any section of trail narrow enough that you’re running single file
    5. Speakers are not allowed
    6. If you forget about your earphones, and a marshal signals you to remove them, you must do so immediately. If you try to argue the point about your music being turned off, your earphones may be confiscated from you until the race finish, and you also risk being removed from the race for your own safety, i.e. disqualified.
  16. The race has an ARC permit number and will be held under ARC rules. We recommend that you make yourself familiar with ARC rules specific to Trail running: http://www.runningclubs.org.uk/rules
Male Category Year Time
M TBA 2024 TBA
M40 TBA 2024 TBA
M50 TBA 2024 TBA
M60 TBA 2024 TBA
Female Category Year Time
F TBA 2024 TBA
F40 TBA 2024 TBA
F50 TBA 2024 TBA
F60 TBA 2024 TBA
Download GPX File Download KML File Detailed Route & Elevation