Arassuil was a Dunadan, and the eleventh Chieftain of the Dunedain. He was the son of Arahad II, and the father of Arathorn I.
During his time, Orcs from the Misty Mountains troubled the lands of Eriador. Most of them were hunted down and killed by Dunedain rangers and elves of Imladris.
Arassuil was succeeded by his son, Arathorn I.