Erebor

Lonely Mountain
Artist's depiction of the Lonely Mountain
J. R. R. Tolkien's legendarium location
Other name(s)	Erebor
Type	Isolated mountain
Ruler	Kings of Durin's Folk: [1] T.A. 1999-c.2200, [2] 2590-2770, [3] 2941-Fourth Age; Smaug T.A. 2770-2941
Notable locations	the Chamber of Thrór, Dale, the Front Gate, the Great Hall, Ravenhill, the secret door
Location	Northeast of Mirkwood
Founder	Thráin I

In J. R. R. Tolkien's Middle-earth legendarium, the Lonely Mountain (Sindarin Erebor) is a mountain in the north of Rhovanion. It is the source of the Celduin River, and the location of the Kingdom under the Mountain. The town of Dale lies in a vale on its southern slopes.

Erebor stood hundreds of miles from the nearest mountain range. Tolkien's map shown in The Hobbit shows the mountain with six ridges stretching out from a central peak that was snowcapped well into spring. The whole mountain was perhaps ten miles in diameter; it contained fabulous lodes of gold and jewels.

The mountain was the habitat for a variety of plants and animals, including thrushes, crows, snails and pines; some of these were endemic sub-species. Perhaps the most well-known were the ravens of Ravenhill, a spur of the mountain. Some wildlife survived the Desolation of Smaug, a dragon who invaded the Mountain and dominated its surrounds for nearly 200 years in the Third Age.

Erebor became the home of the Folk of Durin, a clan of Dwarves known as the Longbeards, after they were driven from their ancestral home of Khazad-dûm. In the latter days of the Third Age, this Kingdom under the Mountain held one of the largest dwarvish treasure hoards in Middle-earth.

Dale, a town of Men built between the two southern spurs of Erebor, formed an economically symbiotic relationship with the dwarves.

The Kingdom under the Mountain was founded by Thráin I the Old, who discovered the Arkenstone there. His son, Thorin I, left the mountain with much of the Folk of Durin to live in the Ered Mithrin (Grey Mountains) on account of the great riches to be found in that range. After dragons plundered their hoards, the Longbeards, led now by Thrór, a descendant of Thorin, returned to Erebor to take up the title King under the Mountain. Under Thrór's reign, Erebor became a great stronghold where the dwarves became a numerous and prosperous people. The Dwarves of Erebor were at that time well known for the making of matchless weapons and armour, and there was great demand for their work by the surrounding peoples. The Longbeards amassed a large treasure hoard during this time.