Dimrill Dale was a valley on the east side of the Misty Mountains, beneath the Redhorn, Silvertine, and Cloudyhead peaks. It was at the eastern end of the Redhorn Pass and was bordered by the Dimrill Stair. Dimrill Dale was the source of the Silverlode river and at its southeast corner was Mirrormere, a sacred lake to the Dwarves of Durin's Folk.
During the Years of the Trees, Durin the Deathless wandered south to Dimrill Dale and founded the Kingdom of Khazad-dûm beneath the surrounding mountains. Thousands of years later, after Orcs had turned the Dwarven city into the "Black Pit" of Moria, the climactic battle of the War of the Dwarves and Orcs was fought here. The Battle of Azanulbizar, which occurred in T.A. 2799, it ended as a defeat of the Orcs and their leader Azog. However, the Dwarves were unable to take back Moria because of the Balrog that still dwelt there.
The Fellowship of the Ring briefly rested in Dimrill Dale after escaping from Moria, following the loss of Gandalf.
