Rhudaur formed the eastern part of Arnor, and stretched from the Weather Hills with Amon Sûl to the river Bruinen. It shared a long border with Cardolan along the Great East Road, and with Arthedain along the line of the Weather Hills.
From the start of its existence, Rhudaur was unfriendly towards the two other successor states, and took part in a bitter conflict with Cardolan over the tower of Amon Sûl and the Palantír associated with the tower.
The last Kings of Rhudaur were not of Númenórean blood, but were descended of Hillmen in service of Angmar. Under their rule the land became a vassal of Angmar, and thus enemies of Cardolan and Arthedain.
The first Stoor Hobbits came into Eriador around 1150. However, due to the increasing hostility of Angmar these Stoors fled the region around 1356, with some of them moving west to Arthedain, and others moving back to the Vales of Anduin.
Angmar annexed and terminated the kingdom in 1409. By this time the Númenóreans were gone from the region, as well as most of the other inhabitants.
There is evidence that after the fall of Angmar at the Battle of Fornost the Angle became home to the remainder of the Dúnedain, and the Rangers of the North established several villages there, where their people lived until the resurrection of the northern Kingdom under King Elessar at the end of the Third Age.