A great forest east of the Misty Mountains, originally known as Greenwood the Great. It becomes Mirkwood after the shadow of Sauron falls upon it from his fortress of Dol Guldur in its southern reaches. Home to Wood-elves ruled by Thranduil in its northern eaves, and to giant spiders, Orcs, and other dark creatures deeper within. Bilbo and the Dwarves pass through Mirkwood during their journey to Erebor.