The Back Door

The Back Door, called the Lower Gate by the goblins, is a hidden exit from the vast network of goblin tunnels beneath the Misty Mountains. It is a low, roughly made passage that leads from the deep heart of the mountain out into a narrow valley between tall peaks, providing a crucial escape route for those who know of its existence. The door itself is a stone portal, guarded by goblins in full armor, and its location is well known to those acquainted with this part of the mountains, though it takes a wizard to navigate the tunnels and guide a party to it. The passage is described as being "a bit low for goblins, at least for the big ones," though even the large orcs of the mountains can traverse it at great speed by stooping low with their hands almost on the ground.

Discovery and Escape

Bilbo Baggins first learns of the Back Door when he overhears Gollum muttering to himself after losing his precious ring. Gollum, suspecting that Bilbo has found the ring and is heading for the back-door, shambles off at a great pace, counting the side-passages as he goes. He stops at a low opening on their left, whispering, "This is the way to the back-door, yes. Here's the passage!" but he dares not enter, smelling goblins down there. Bilbo, desperate to escape, leaps over Gollum's head and speeds down the new tunnel. The passage slopes down, then climbs steeply, and at the bottom of a short incline, Bilbo sees a pale out-of-doors light filtering around a corner. He scuttles to the end and finds a great stone door left standing open, guarded by goblins who see him and rush upon him. He only escapes by slipping on the ring, becoming invisible, and squeezing through the crack of the door after a struggle that bursts his buttons.

Significance and Aftermath

The Back Door is a vital element in the dwarves' escape from the goblin realm. After Bilbo's yell alerts Gandalf to the capture, the wizard follows the prisoners to the edge of the great hall, works magic to kill the Great Goblin, and then leads the dwarves through the tunnels. Gandalf knows all about the Back Door, which the goblins use as a way of escape and as a route into the lands beyond, where they come in the dark to do great damage. It is always guarded, and after the dwarves' escape, the goblins guard it doubly. The passage leads out to a narrow valley between tall mountains, and Bilbo, after emerging, finds himself on the other side of the Misty Mountains, at the edge of the Land Beyond. This escape marks a turning point in the adventure, allowing the company to continue their quest eastward toward the Lonely Mountain.