Trail Running calendar near Harwell 2025-2026

We have found 399 Trailruns within 80 miles of Harwell. See below where and when you can find the races.

Run the dramatic Cheddar Gorge on trails across the Mendip Hills, from a fun 1k up to a full marathon, with cliff top views, meadows and rugged rock underfoot. Finishers of 6km and longer earn a two sided event medal.

Tackle scenic but hilly forest trails at the Wendover Woods Half Marathon and 10k on 14 June 2026, with a friendly junior run and on the day entries if available. Spectators can enjoy a cafe, forest walks and family activities.

Run through Hertfordshire countryside from 3 Brewers Brewery with 10 km and 5 km options over mostly off road trails, woodland and farm tracks. Finish with a medal, chip timing, a pint and live jazz for a festive post race vibe.

The Phoenix Denbies Marathon & Half Marathon, held at Denbies Wine Estate in Dorking, Surrey, offers a unique off-road trail running experience on a flat-ish 1-mile loop with slight inclines. Scheduled for June 2026, the event features flex..

Beyond London on 20 June 2026 offers scenic trail runs through parks, woodlands and canal paths, finishing in Richmond. Choose 55 km from Woolwich or 25 km from Upper Norwood, with signed routes, GPX files, aid stations and a finisher medal..

Event overview P24 - The Longest Attended Day is scheduled for Saturday 20 June 2026 at Denbies Wine Estate in Dorking, Surrey (RH5 6AA). The format requires participants to run 1 mile at the same time each hour, repeated 24 times across 24..

The Centaur 100 Mile Ultra, hosted by Phoenix Running, is a unique 100-mile trail running event held at Denbies Wine Estate in Dorking, Surrey. Designed for both seasoned ultra runners and first-timers, the race features a flat-ish, single..

Race to the King on 20 June 2026 invites runners to explore the South Downs and Monarch's Way at West Dean Gardens, with coastal and castle views. Distances from 30 to 100 km include full support, food stops and a hot finish meal.

Run a scenic point to point trail through Buckinghamshire, Bedfordshire and Northamptonshire with a 50 mile ultra or a marathon, both finishing at Marlow Park, Grafham Water. Waymarked routes, aid stations and medals for all finishers.

Solstice at the Lakes is a timed trail running event held at Leybourne Lakes Country Park in Kent, featuring 6-hour, 12-hour, and 24-hour race options. Participants can compete solo or in teams (pairs or up to four runners) on a flat, fast,..

The Midsummer Munro will take place in Walton on the Hill on Sunday 21 June 2026. You can run 13 miles.

UTMB Index

Run the Martian Race at Horsell Common on 21 June 2026 and follow routes through the sandpits immortalised in H.G. Wells The War of the Worlds. Volunteer organised and charity focused, with distances for all ages.

Take on the Dunstable Downs Half Marathon, a scenic 21.2 km trail with steep climbs and panoramic countryside views. Limited to 300 runners, this rugged UTMB World Series qualifier promises a memorable off road challenge.

UTMB Index

Join the Summer Run the Seasons at Cowdray Estate on 26 June 2026 for scenic 5km, 10km and dog friendly canicross routes past the polo lawns, ruins and the South Downs. Celebrate at the finish with an interlocking medal, free photos and a B..

Tackle a full marathon over three days at the Colworth Marathon Challenge on the scenic Colworth Estate. Choose one, two or all three races and enjoy free camping, family entertainment and children's races for a festival feel.

Take on farm trail laps at Hyde Hall Farm with distances from 5k to ultra, including a Heavy Half option. On site parking and a bespoke finisher medal make for a friendly, flexible event.

Enjoy an inaugural trail run from Housedean Farm on the South Downs, with scenic views across Lewes and Plumpton. Choose the half marathon or 10K on mixed gravel and well kept trails, with aid stations and a finisher medal.

Take on multi lap 5K loops at the Snickerthon in scenic Chasewater Country Park with distances from 5K to full marathon. Enjoy a relatively flat course, finisher medal and maybe a Snickers plus refreshment stops.

Choose from 10K, half marathon, marathon or 50 km on scenic, well marked trails through Salcey Forest. A friendly community day with generous time limits, forest underfoot and a medal plus drink for every finisher.

Enjoy scenic Thames Valley trails at Marlow Rugby Club with 5K, 10K and Half Marathon options on well marked off road courses. Chip timing, free race photos and a themed finisher medal make this a fun, sustainable event for all abilities.