Altra Kielder Marathon: Course, Elevation & Route Profile

Course & Elevation

Start and finish are at Kielder Waterside on the south shore. From there the lap first crosses the Bull Crag peninsula, then follows the shoreline west to Kielder village at the head of the lake, comes back east along the North Shore and finally crosses the Kielder Dam to the south side. The closing kilometres pass Tower Knowe on the way back to the finish.

The profile has no structure in the usual sense. The whole lap sits inside a height band of about forty-five metres, between 186 and 231 m, and still totals 521 metres of climbing. The largest single climb is forty-two metres, at kilometre fifteen; only 1.6 per cent of the course is steep. What defines it is the constant undulation: a third up, a third down, a third flat, alternating in short bursts the whole way round.

The surface is well-made forest track throughout - the organiser says trail shoes and ordinary trainers both work. The setting is Kielder Forest, the remotest corner of Northumberland: no traffic, few spectators, but a free park-and-ride and shuttle buses to some of the vantage points. The field is small for a British marathon - 621 runners finished in 2023. The race was founded in 2010 by Steve Cram, and 2026 is the sixteenth edition of the weekend. Two hard cut-offs structure the day from outside: the dam at about mile 17.25 by 15:45, and Tower Knowe at about mile 19 by 16:00.

Pacing Strategy

On a course with no long climb anywhere, fatigue comes from repetition rather than from one key section. Over two thirds of the lap runs either gently up or gently down, and none of the undulations lasts long enough to change gear for. Take them one at a time, accelerating back to pace after each, and by thirty kilometres you have hundreds of small surges in your legs.

The trap is the surface combined with how it looks. The Lakeside Way is well built and reads as flat; the splits still come out noticeably slower than on road. Pace the opening hours off road race times and you are objectively running too hard. Run the whole lap to effort and heart rate, not to the watch.

The race is decided in the last third, between the North Shore and the dam. That is also where the two cut-offs sit, and where the undulation turns into a problem because it stops allowing any recovery. Run the first twenty kilometres conservatively and evenly and you can lift again from the dam, past Tower Knowe, to the line.

Training plan for Altra Kielder Marathon: 12-week build

For age-group runners the Kielder Marathon takes roughly three to just under six hours; with a 10:15 start, the course closure at Tower Knowe at 16:00 sets a clear ceiling. The demand is an aerobic one with continuous small changes of load - not a marathon with long settled stretches, but one where neither muscles nor pace ever really settle across four hours.

That dictates the main training stimulus: long runs on undulating unsurfaced ground. Not hill training in the classic sense, but thirty to thirty-five kilometres on forest and gravel track with constant small rises and falls, run at constant effort rather than constant pace. Practising that teaches exactly what the course asks: not to push over the crests and not to coast in the dips.

Strength endurance for the legs belongs with it. Five hundred metres of climbing broken into hundreds of individual undulations loads calves and quads differently from one long ascent; squats, single-leg work and moderate-pace downhill running prepare for that. Sure-footedness on good but wet forest track is worth practising too - the surface is firm, but often damp in October.

Conditions are those of an October Sunday in northern English forest: cool, frequently damp, and considerably colder standing at the start than running. The organiser's own FAQ suggests pulling a bin bag over your head before the start if it is drizzling or cold. With no crowds and almost no buildings, the mental side counts as well: long stretches alone by the water with nothing outside to run off.