Older than the city of Waterdeep itself, Undermountain is a massive dungeon that descends deep under the city to depths that few can fathom. Constructed by the mad mage Halaster Blackcloak, it is rumored to be filled with traps, monsters and cursed magic most foul from across the multiverse. The only known entrance to the Undermountain is within the The Yawning Portal.

Undermountain Secrets

There are many secrets hidden within the halls of Undermountain. Below is a list of secrets uncovered so far, a list which is, by no means, comprehensive.


It is rumored that within the halls of Undermountain lies an entrance to Skullport.


This noble house was exiled from Waterdeep years ago. It is rumored that they have something to do with Undermountain.

River Sargauth

This underground river is said to border an ancient dwarven fortress and has something to do with Skullport.

Cathedral of Blood

This vampire den is located with Undermountain.

Halaster’s Tower

Whatever this is, it is only accessible from level 23.


Whatever this is, it is only accessible from level 16.

The Xanathar

This organization seems to be popular with goblins hailing from Skullport.

Goblin Market

A thriving, goblin-run market free from the influence of the The Xanathar.

Azroks Hold

A ruined section of an ancient dwarven fortress run by a militant hobgoblin legion led by Warlord Azrok.

Lost Temple to Dumathoin

This lost temple to the dwarven god of buried secrets is deep within the dungeon.

←Back to Waterdeep


Dungeon of the Mad Mage IanGould IanGould