The Ered Wethrin ran along the southern and eastern edges of Hithlum and had few passes. The north-western boundary of Hithlum was formed by the Ered Lómin which curved to meet Helcaraxë. The land of Nevrast was separated from Hithlum by the southern part of the Ered Lómin. Nevrast was usually seen as part of Hithlum but more closely resembled the rest of Beleriand. Lammoth lay to the west. Hithlum's climate was cold and wet, however, the soil was quite rich. The Ñoldor made their first landing at the Firth of Drengist and first camped at the shores of Lake Mithrim.
Hithlum became the realm of the ruling Ñoldor living in exile in Middle-earth. Hithlum contained Mithrim and Dor-lómin. Mithrim was the seat of the High Kings of the Ñoldor while Dor-lómin later became a fief of the House of Hador.
During the later part of the First Age, Hithlum was repeatedly attacked by the forces of Morgoth. Hithlum was lost to Morgoth after the Nírnaeth Arnoediad. The Men of the House of Hador in Dor-lómin were either scattered, killed, or enslaved, while the Ñoldor of Mithrim who failed to flee were enslaved in Morgoth's mines. When Morgoth betrayed the Easterlings, he imprisoned them in Hithlum.
Hithlum is North Sindarin for Mist-shadow after the sea mists that sometimes formed there. The index to the Silmarillion refers to it as meaning Land of Mist. Its Quenya counterpart is Hisilómë and its Sindarin counterpart is Hithlaw or Hithlû.
|Foreign Language||Translated name|
|Chinese (Hong Kong)||希斯隆|
|Kazakh||Һітһлұм (Cyrillic) Hithlum (Latin)|
|Serbian||Хитлум (Cyrillic) Hithlum (Latin)|
|Uzbek||Ҳитҳлум (Cyrillic) Hithlum (Latin)|
- The Silmarillion, Index of Names
- The Atlas of Middle-earth, The First Age, The Elder Days, "Beleriand and the Lands to the North"
- The Silmarillion, Quenta Silmarillion, Chapter XIV: "Of Beleriand and its Realms"
- The Silmarillion, Quenta Silmarillion, Chapter XV: "Of the Noldor in Beleriand"
- The Silmarillion, Quenta Silmarillion, Chapter XVII: "Of the Coming of Men into the West"
- The Silmarillion, Quenta Silmarillion, Chapter XX: "Of the Fifth Battle: Nirnaeth Arnoediad"
- The Silmarillion, Quenta Silmarillion, Chapter XXIV: "Of the Voyage of Eärendil and the War of Wrath"