Fornost
In the fiction of J. R. R. Tolkien, Fornost Erain (Sindarin 'Northern-fortress of the Kings' from for(n) (north) + ost (fortress); "Norbury of the Kings" in Westron) was a city of Eriador in the north of Middle-earth. It was located at the south end of the North Downs, about 100 Númenórean miles north of Bree; after Fornost Erain was abandoned, the site became known as Deadman's Dike.
It is not known when Fornost was founded, or when the kings of Arnor moved there from Annúminas; but most probable is that when Eärendur died in T.A. 861, and Arnor was divided into three kingdoms, Eärendur's eldest son Amlaith moved to Fornost to rule his kingdom of Arthedain.
In T.A. 1974, Arthedain was overrun by the forces of Angmar, they captured Fornost, and King Arvedui fled into the northern wastes and was lost in the Ice Bay of Forochel. In the following year, a fleet from Gondor led by Eärnur landed at Mithlond, fought the Witch-king of Angmar in the plains west of Fornost, and defeated him and his armies, although the Witch-king himself escaped.
