In J. R. R. Tolkien's legendarium, the Lonely Mountain is a mountain northeast of Mirkwood. It is the location of the Dwarves' Kingdom under the Mountain and the town of Dale lies in a vale on its southern slopes.
In The Lord of the Rings, the mountain is called by the Sindarin name Erebor. The Lonely Mountain is the destination of the protagonists, including the titular Hobbit Bilbo Baggins in The Hobbit, and is the scene of the novel's climax.
The mountain has been described as the goal of Bilbo's psychological quest in The Hobbit; scholars have noted that both it and The Lord of the Rings are structured as quests to a distant mountain, but that the quests have very different motivations. Further, the mountain is a symbol of adventure in The Hobbit, and of Bilbo's maturation as an individual, while to the Dwarves, it stands for the gain of beauty in return for loss of life.
Fictional mountain
Erebor stands hundreds of miles from the nearest mountain range. Tolkien's rendering of Thrór's map in The Hobbit shows it with six ridges stretching out from a central peak that was snowcapped well into spring. The whole mountain is some ten miles in diameter; it contains an immense wealth of gold and jewels.
Origins
Erebor becomes the home of the Folk of Durin, a clan of Dwarves known as the Longbeards, after they are driven from their ancestral home of Khazad-dûm. In the latter days of the Third Age, this Kingdom under the Mountain holds one of the largest dwarvish treasure hoards in Middle-earth. The Kingdom under the Mountain is founded by Thráin I the Old, who had discovered the Arkenstone there. His son, Thorin I, leaves 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 plunder their hoards, the Longbeards, led now by Thrór, a descendant of Thorin, return to Erebor to take up the title King under the Mountain. Under Thrór's reign, Erebor becomes a great stronghold where the dwarves are numerous and prosperous.
Bilbo, Thorin, and Thorin's company of twelve other Dwarves travel to the Lonely Mountain to regain the treasure. They plan to use the secret door, whose key and map Gandalf had obtained from Thráin, whom he had found at the point of death in the pits of Dol Guldur.
Smaug, enraged by the theft, emerges from the mountain and flies south to destroy Lake-town, which he suspects is the source of the "thieves". During this attack Smaug is killed by Bard the Bowman; Thorin claims the mountain on learning of Smaug's demise. However, the Men of Esgaroth, supported by Thranduil and the Elves of Mirkwood, march in force to the mountain to demand a part of the dragon's hoard as recompense for the destruction. Thorin, mad with greed, refuses all claims and sends word to his second cousin Dáin II Ironfoot, chief of the Dwarves of the Iron Hills, who brings reinforcements. Before battle can begin, an army of Orcs and Wargs descends on Erebor. Dwarves, Elves, and Men join ranks against them, leading to the Battle of Five Armies. Thorin's nephews Fíli and Kíli are killed, and Thorin is mortally injured; he dies shortly afterwards. The title of King under the Mountain passes to Dáin.
Erebor in The Lord of the Rings
With the restoration of the Kingdom under the Mountain, the area becomes prosperous again. Dale is rebuilt under Bard's leadership, and Dwarves and Men reforge their friendship. Some of the Dwarves, led by Balin, leave Erebor to reclaim the ancient Dwarvish Kingdom of Moria.
In the War of the Ring, an emissary from Sauron, the lord of Mordor, twice comes to Erebor and speaks to Dáin. The messenger asks for assistance in finding Bilbo Baggins and retrieving a stolen ring, and in return offers Moria and three of the seven Dwarf rings to Dáin, who declines to reply. Sauron's northern army, including many Easterlings, then attacks; Dale is overrun, and many Dwarves and Men take refuge in Erebor, which is promptly surrounded. Dáin is killed before the gates of Erebor defending the body of his fallen ally King Brand of Dale. Dáin's son Thorin III Stonehelm and King Bard II withstand the siege and rout Sauron's forces.
Analysis
Goal of psychological quest
The Jungian psychoanalyst Dorothy Matthews, viewing The Hobbit as a psychological quest, writes that the Lonely Mountain is an apt symbol of Bilbo's maturation as an individual, as the place where he takes on a leadership role and acts and makes decisions independently. The Tolkien scholar Jared Lobdell comments that he is "profoundly unsympathetic" to Matthews's approach, but that she "carries it off well". Lobdell explains, citing C. S. Lewis's essay "Psychoanalysis and Literary Criticism", that many different stories could, for instance, have the same Freudian interpretation, but be quite different as literature. He remarks on the other hand that a psychoanalytic approach is at least richer than a purely materialistic one.
The scholar of children's literature William H. Green calls the Lonely Mountain the fourth and final stage of Bilbo's education. He identifies multiple parallels and repetitions of structure between the stages, each one involving a journey, privation, and "unlikely escape". The Lonely Mountain stage, too, symbolically echoes the first stage in the Shire: before setting out, Bilbo was peacefully smoking a pipe of tobacco at his own front door; at the mountain, the smoke is the dragon's, and its meaning is anything but peaceful. The Christian writer Joseph Pearce views the journey to the Lonely Mountain as a "pilgrimage of grace", a Christian bildungsroman, at its deepest level. Pearce states further that Bilbo's quest to the mountain parallels Frodo's quest to a different mountain, Mount Doom, which he calls "a mirror of Everyman's journey through life".
Two scholars of literature, Paul Kocher and Randel Helms analyse Bilbo's journey to the Lonely Mountain, describing it as the goal of his quest and the point at which it is achieved. Both compare the quest in The Hobbit with that of The Lord of the Rings, noting that the two novels, for all their differences including the reason for the quests, are structurally similar.
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|+ Randel Helms's analysis of quest structure in The Hobbit and The Lord of the Rings
Amelia Harper, in the J. R. R. Tolkien Encyclopedia, writes that the mountain's history, as usual for the Dwarves, was a tale of "beauty gained and lives lost".
"Erebor", specifically the southern spurs of the Mountain and Dale, is a playable map in The Lord of the Rings: The Battle for Middle-earth II. It has three gates, including the one Tolkien described and two which cannot be closed, to allow those playing as invading forces to easily enter the stronghold.
The Lonely Mountain appears in Peter Jackson's film adaptations of The Hobbit: An Unexpected Journey, The Desolation of Smaug, and The Battle of the Five Armies. The actual setting was Mount Ruapehu in New Zealand.