Mantol-Derith was a city situated in a huge underground cavern three miles below the surface.
It was heavily guarded and protected by strong magic. Its exact location was not known by many. The cavern was naturally formed by water due to its proximity to the Darklake, and was filled with waterfalls, pools, and streams. Its walls were filled with multicoloured crystals and gems. Bridges across the various streams were carved from crystal. The nearest drow settlement to Mantol-Derith was Menzoberranzan, but was formerly Ched Nasad.