Middledark

Located three to ten miles below the surface, this layer was where most of the Underdark cities are located. From the infamous Grackelstugh or Menzoberranzan to the lesser known villages of the kuo-toa and myconids, the largest and most prosperous cities exist in this area.
The middledark is far more connected than the upperdark, with most areas found in the main veins that flow through the deep parts of the earth. It also has a few connections to the lowerdark. Many of these are established fortresses, some even manned by races who have hated each other for a millennia. The fear and cooperation sometimes found at these fortresses and the monumental levels of defenses and magic contained within speak volumes for the terrors they seek to prevent from ascending form the lowerdark.

Mapping

The middledark is a honeycombed labyrinth of vast tunnels that range in depth by many miles. Enormous caverns, pockets of magma rising from the Lowerdark and miles upon miles of tunnels are the predominant features found here. Vast tunnels often bored by Purple Wyrms, Beholders or magma flows pocket the world.
The area is far too massive to map, and instead the various landmarks can be visited given enough travel time. The areas contained within this document are settlements found in the Middledark.

Inhabitants

The middledark is where most of the cities and larger settlements of the underdark races can be found. The same races as the Upperdark are commonly found in the Upperdark, with far more monsters and dangerous denizens from the lower depths.
Troglodytes, Myconids, Duergar, Drow, Quaggoth, kuo-toa, Derro and svirfneblin have permanent settlements in the middledark.

Location under

The Underdark