Cardolan (Sindarin for "Red Hill Country") is the name of one of the three kingdoms into which Arnor was divided in T.A. 861 (the other two being Arthedain and Rhudaur). Cardolan was bounded to the west by the Baranduin (Brandywine) River, to the east by the Mitheithel (Hoarwell) River, to the east and south by the Gwathló (Greyflood) River, and to the north by the Great East Road. It was thus the southernmost division of what was once Arnor.
Cardolan was an ally to Arthedain for some six centuries, until in T.A. 1409 a large invading force from Angmar destroyed Cardolan and slew its last king. Soon after the Great Plague of T.A. 1636, the Witch-king of Angmar raised fell spirits to inhabit Tyrn Gorthad, and what was once the capital of Cardolan is now known as the Barrow-downs.
For more information on Cardolan, please see the following link:
- Wikipedia: Cardolan