100 mile ultra marathons

100 mile ultra marathons

The UK's most comprehensive calendar of 100 mile ultra runs - some of the biggest endurance challenges on Earth! Search by date, location or map to find a 100 mile ultra marathon near you or browse to discover your perfect event.

View all 100 mile ultra runs

100 mile ultra runs

The longest of the ultra distances, 100 mile ultra marathons are a big challenge for any runner. But distance isn't always the key challenge with long ultra runs - the total ascent gives a much better indication of how hard it will be. Select your location to find 100 mile ultra runs in your area or scroll down to browse events coming up.

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100 mile ultra runs in 2025

Featured events are listed below - select a month/region or the map view to see all events.

Can you survive Farmmageddon? Held over 32-hours, runners will cover the fantastic 5.3K loop through the lovely grounds of Hyde Hall Farm and receive a t-shirt, buckle and medal to prove it!
  • Sat 24 May
  • £163-£165
Buntingford, Hertfordshire, UK

Farmmageddon | 100 Miles

Can you survive Farmmageddon? Held over 32-hours, runners will cover the fantastic 5.3K loop through the lovely grounds of Hyde Hall Farm and receive a t-shirt, buckle and medal to prove it!

  • 100 miles trail running
  • Chip timing
  • Enter online
  • Undulating
  • Traffic free
  • Age 20 & over
  • Ultra runs
Yr Wyddfa (Snowdon) is the highest mountain in England and Wales. Your challenge is to ascend and descend as many times as possible in 24 hours - solo or as a relay team.
  • Sat 12 - Sun 13 Jul
  • £121.99-£251.99
Caernarfon, Gwynedd, UK

Black Diamond Yr Wyddfa Snowdon24

Yr Wyddfa (Snowdon) is the highest mountain in England and Wales. Your challenge is to ascend and descend as many times as possible in 24 hours - solo or as a relay team.

  • 24 hrs trail running
  • Chip timing
  • Enter online
  • Mountainous
  • Relay
  • Age 18 & over
  • Ultra runs
  • Sat 7 Jun
  • £199
Castle Douglas, Dumfries and Galloway, UK

Ultra Scotland 100

Take on 100 historic miles across the beautiful Southern Upland Way - one of the greatest trails in the UK. Ultrarunners will tackle several ascents, pass through forests, valleys and by lochs.

  • 106 miles trail running + 4611 m ascent

100 mile ultra runs near you

Select your location for 100 mile ultra marathons in your area.