Land of Mist

To the north of Beleriand was a wide land ringed by mountains and hills, and it was here the Noldor first encamped when they returned to Middle-earth, in the southeastern part of the land, a place known as Mithrim. At that time Morgoth sent great clouds out of Thangorodrim that shrouded the region, and it was given the High-elven name of Hisilómë, the Land of Mist, or literally 'mist-gloom'. The name remained even after the mists of Morgoth had cleared, but it became transformed by the Sindar who dwelt there, and the Land of Mist is most usually known in the histories of those days by the Sindarin name of Hithlum.