Rhudaur was one of the three kingdoms of Arnor, located in the northwestern part of Middle-earth. It was established after the division of the kingdom of Arnor into three separate realms: Arthedain, Rhudaur, and Cardolan. Rhudaur was situated to the southeast of Arthedain and was characterized by its rugged terrain and dense forests. The kingdom of Rhudaur eventually fell into decline due to internal strife and external pressures, particularly from the Witch-king of Angmar. By the late Third Age, Rhudaur had been largely overrun, and its people were either driven out or assimilated into other cultures, marking the end of its existence as a distinct realm.