A 100 km ultramarathon following the Serpent Trail through the greensand landscapes of West Sussex, linking Haslemere to Petersfield via heathland, woodland and rural tracks. The route traverses rolling terrain across the South Downs hinterland, with sustained climbs and descents but no extended mountain sections. Underfoot conditions vary between sandy trail, forest path and firmer track depending on weather. Course marking, navigation approach and aid station locations are defined by the organiser’s official race information.

• Other races at the same event:
Serpent Trail 50K Ultra Marathon