The Second Hall was one of many Halls of Khazad-dûm. Between the Second and the First Hall - counting from the entrance of the city - lay the ill-fated Bridge of Khazad-dûm in the First Deep. The hall's pillars were notable for being smooth and black, carved like trees, with the boughs holding up the ceiling.
In T.A. 2994, Orcs joined battle with the Dwarves of Balin's Colony in the hall. During the ensuing brawl, Lóni, Náli and Frár were killed while the rest of the Colony escaped to the Seventh Level, allowing the Orcs to reclaim the Hall.
It was the largest of the halls to be encountered by the Fellowship of the Ring as they traversed Moria from west to east. On their way to the First Hall from the Second Hall, they met Durin's Bane at the Bridge of Khazad-dûm, and Gandalf fell into the chasm.