Eregion

Eregion or Hollin was a kingdom of the Ñoldorin Elves during the Second Age, located near the West Gate of Khazad-dûm. Rarely for an Elven Kingdom, relations with the Dwarves were cordial and both sides traded freely.

History
Eregion was, from SA 750, ruled by Galadriel and Celeborn from its capital of Ost-in-Edhil. After SA 1350, they crossed the Misty Mountains to Lothlórien, their new kingdom.

From SA 1350, the Gwaith-i-Mírdain under Celebrimbor, the last of Fëanor's House left in Middle-earth, ruled Eregion. Annatar, the Giver of Gifts, befriended Celebrimbor and aiding him in the making of the Nine and the Seven of the Rings of Power. Celebrimbor made the Three in secret and these were never touched by Annatar's hands.

When Annatar was later revealed to be the Dark Lord Sauron, Celebrimbor and his people tried to stop the Rings from entering Sauron's possession but could only rescue the Three: Vilya, Narya, and Nenya. Eregion itself was attacked and destroyed in the War of the Elves and Sauron in the year SA 1697. The few survivors of the war found refuge in either Lindon or Lothlórien, while others led by Elrond founded Imladris.

In the Third Age, by the time that the Fellowship of the Ring reached Khazad-dûm, the land was pleasant but unpopulated. Only the scattered ruins of Elven cities and the few remaining holly trees indicated its former glory.

Etymology
Eregion should not be pronounced as in English region: the g is the g in get. The pronunciation is. Both Eregion and Hollin refer to the great holly trees of the region.