The ALTAR 100k is an ultra-endurance event held at Beyond the Trees Avondale Forest Park in County Wicklow. Runners complete 31 loops of a 3.2km forest trail circuit, starting and finishing at the central aid station near the car park. The course winds through the mature woodland of Avondale Forest Park on forest trails and paths, with gentle undulation throughout. A 100k relay option is also available for teams of up to five. A central aid station stocked with water, snacks and ALTAR Speed Dust is accessible every loop, and drop bags are permitted. On-site facilities include a café, pizzeria, playground and toilets. Two full ambulance crews are on site for the duration of the event.