Ultra distance running covers races over a distance greater than marathon distance (over 42.2k).
If the thought of that appeals, rather than putting you off, then carry on reading!
Events can be held on a range of surfaces, including track and road but also over hilly or mountainous terrain. As such ultra races are held under the UKA Rules of Competition for the endurance discipline that most closely reflects the nature of the event.
In the same way as other running events, ultra distance events can be held as a race to see who covers a set distance first. Typical race distances include 50K, 100K, 50 miles, and 100 miles, with ultra-distance races over other distances as well. But ultra distance races also include events where the runners have to cover the furthest possible distance in a set time – for example 12 or 24 hours – with results determined by the distance a runner has covered in the time given.
Some events extend to being over several days (multi day events). In some of these competitions athletes have to be self-supported and carry all they need for the duration of the race, in other events runners are able to have support.