Altra Kielder Marathon Weekend is a scenic trail running festival set around Kielder Water & Forest Park in Northumberland, billed as “Britain’s most beautiful marathon.” The event features a variety of distances including the Marathon, Half Marathon, 10K, Gravel Duathlon and Junior races, all taking place over a weekend of trail and off-road running. It attracts runners from across the UK and beyond, offering a mix of challenge, natural beauty and community spirit on mostly off-road terrain. 

Key Details

Dates: Saturday 3 October and Sunday 4 October 2026
Location: Kielder Waterside and Kielder Forest Park, Northumberland
Organiser: Events of the North / Kielder Marathon organisers

Event Types

• Marathon — a full off-road marathon around Kielder Water and forest trails

• Half Marathon — slightly shorter off-road course around the lake and trails

• 10K — shorter trail distance ideal for a scenic run

• Gravel Duathlon — run/bike/run off-road challenge

• Junior Races — shorter distances for younger runners

Race Description

The weekend begins with events such as the 10K and gravel duathlon on Saturday, followed by the Marathon, Half Marathon and junior races on Sunday. All distances are run predominantly on packed forest trails and lake paths along the shore of Kielder Water, making the courses largely off-road and well suited to trail or mixed terrain shoes. Organisers emphasise the stunning natural surroundings, with deeper forest sections and open lakeside paths giving both challenge and memorable scenery.

What’s Included

• Finishers’ medal and goody bag for all participants in each distance

• Free park & ride shuttle bus system for runners to and from start areas

• Secure baggage drop onsite

• Aid stations with refreshments and local produce

• Prizes for top male, female and veteran age group finishers

• Post-race refreshments and race village atmosphere

Additional Information

• The marathon and half marathon courses start on Sunday morning around 10:15 AM, with the 10K and duathlon on Saturday afternoon around 1:00 PM. 

• Cut-off times are enforced at key checkpoints to ensure runner safety and event flow.

• Junior events typically take place mid-morning on Sunday and are open to younger age groups.

• Entry closes at midnight on 30 September 2026, or when sold out.

• Courses are traffic-free and mainly off public roads, following lakeside trails and forest tracks.