Underdark
The Underdark is a Region of Faerûn, and consists of multiple locations in Act One of Baldur's Gate 3. It is a vast series of caverns and tunnels devoid of sunlight but full of dangerous creatures and even more dangerous mushrooms, but also contains a multitude of alchemical ingredients that are hard to find elsewhere. The Underdark in Baldur's Gate 3 is only a small portion of the true Underdark. The Drow, Duergar and Deep Gnomes are native to the Underdark.
Access
Due to its immense size, there are multiple access points into the Underdark from over-land. All of them involve travelling (or falling) deep into the depths of the world.
The following locations contain known access points into the Underdark:
- Ladder from the Defiled Temple, arriving in the Selunite Outpost.
- Elevator from the Zhentarim Hideout, arriving in the Storehouse.
- Mushroom circle in the Overgrown Tunnel to a corresponding circle in Torchstalk Gulch
- Falling into the hole in the Whispering Depths, arriving in the Minotaur Hills.
Areas
Storehouse
The Storehouse is a location in the most north-eastern quadrant of the Underdark map. This primary area, when labelled on the player minimap, is recognisable for its aging pale wooden interior and is free of any enemies.
Enter the Underdark through this area when departing from the over-world's Zhentarim Basement.
Minotaur Hills
Considered part of the Storehouse, this unnamed area of the Underdark is recognisable thanks to its bright green grass and whimsical red mushrooms with swirling paths featuring wandering Minotaurs. This area is directly to the south of the Storehouse via the rope netting.
Ebonlake Grotto
The Ebonlake Grotto is recognisable for its densely packed oversized mushrooms, and roaming Myconids amidst which reside several NPCs and merchants.
Myconid Minefield
Considered part of the Ebonlake Grotto and in its south-east part, this nameless area of the Underdark is recognisable for being full of dangerous mushrooms such as Timmask and Bibberbang, which are a particularly dangerous combination with Torchstalk mushrooms that can quickly turn the area into a series of explosions.
Giant Bird Nest
Considered part of the Ebonlake Grotto and to its south-west, this unnamed area is an unremarkable corridor connecting Ebonlake Grotto, the Dread Hollow and the Decrepit Village. It is most recognisable for the giant bird's nest.
Dread Hollow
The Dread Hollow is a location in the north-west of the Underdark. This area is recognisable for the large and brightly shining Sussur Tree, as well as the roaming Hook Horrors and hostile wizard, Filro the Forgotton, living along its branched roots. A Bulette can also be spotted in the area.
To the south lies the tombstone of Myrna, a pet dog of Lenore.
Bibberbang Grotto
North-east of the Sussur Tree in the Dread Hollow section of the Underdark, the Bibberbang Grotto is an unnamed area of explosive and densely growing Bibberbang mushrooms, trapping Baelen Bonecloak.
Arcane Tower
The Arcane Tower is a location in the south-west corner of the Underdark map. This primary area, when labeled on the player minimap, is recognizable by its neatly built stone entryway that opens to a front garden featuring Arcane Cannons.
Torchstalk Gulch
Considered part of the Arcane Tower and to its east, this unnamed area of the Underdark is recognisable by its dark brown paths paved with deep red mushroom clusters and spots of Torchstalk that cast floating embers into the air. The corpse of an unfortunate Drow can be found, having been killed by an unexpected fall. Can be spoken to with 
, which is detailed further down.
A few mushroom circles can be found here, one of which leads to the Overgrown Tunnel.
Festering Cove
The Festering Cove is a partially hidden location on a separate Underdark map, containing the Kuo-toa worshipping their god, BOOOAL. It can be reached by climbing down the cragged rock in Torchstalk Gulch X: 80 Y: -241.
Selûnite Outpost
The Selûnite Outpost is a location in the SE corner of the Underdark map. This area is recognisable by its crumbling stone walls, grated windows, and tattered blue banners to the goddess Selûne. A statue of the goddess holds up a bright moonstone, which channels energy into the front gate's defences.
The Outpost can be reached from the Shattered Sanctum.
Ancient Battlefield
Directly north of the Selûnite Outpost, this unnamed area of the Underdark is recognisable by its field of scattered wooden barricades and long-dead skeletons of ancient fighters.
Petrified Battlefield
To the west of the Selûnite Outpost, this nameless area of the Underdark is recognisable by its purple Glowing Gems and several petrified Drow as well as one Spectator.
Decrepit Village
The Decrepit Village is the central location of the Underdark and fairly vertical. It is recognisable for its ramshackle wooden structures and rope netting enclosures.
Beach
The lowest level of the Decrepit Village, this unnamed area features a sandy beach strewn with the bodies of dead Deep Gnomes and Duergar. A boat rests at one dock, ready to take the player to Grymforge based on the story path of their choosing.
Grymforge
Grymforge is an expansive and abandoned settlement location on a separate map, containing the Adamantine Forge. It is accessible via the boat at the Decrepit Village.
Regional Waypoints
The following 
are available within the Underdark.
- Beach Decrepit VillageX: 22 Y: -209
- Selûnite Outpost X: 180 Y: -235
- Myconid Colony Ebonlake GrottoX: 101 Y: -101
- Sussur Tree Dread HollowX: 49 Y: -140
- Grymforge X: ? Y: ?
- Ancient Forge X: ? Y: ?
Characters
Notable NPCs
Arcane Tower:
Decrepit Village:
Dread Hollow:
Ebonlake Grotto:
Festering Cove:
Petrified Battlefield:
Grymforge:Creatures
Notable loot
Quest Items
Other notable
The following loot may all be obtained in the unnamed areas of the Underdark region (additional loot is available in named locations within the Underdark) whether looted, purchased, or obtained as a quest reward: [Needs Verification]
Hidden treasure
- Dog Collar X: ? Y: ?: Dig up the grave in Dread Hollow South
- Phalar Aluve X: 117 Y: -192: Pass the Strength or Religion check to free this sword from a stone
- Buried Chest X: ? Y: ?: Pass the check to dig up this chest near the Petrified Battlefield
- Giant Nest X: ? Y: ?: Climb the mushrooms to reach the chest contained in this Giant Bird Nest
- Buried Wooden Chest X: ? Y: ?: Pass the check to dig up this chest near the center of the Bibberbang Grotto in Dread Hollow
Related quests
The following quests may all be found in unnamed areas of the Underdark region (additional quests are available in named locations within the Underdark):
Speak with Dead
Throughout the Underdark are a few unnamed, dead NPCs can that provide insights about the area.
Dead Drow
Located in Torchstalk Gulch, just at the foot of the mushroom platform wall leading to the Overgrown Tunnel.
Player: Who are you?
- Dead Drow: House Vandree... far scout... searching...
- Player: What where you searching for?
- Dead Drow: Quick path... to surface...
- Player: What where you searching for?
Player: What happened to you?
- Dead Drow: Threw backpack... too light... fell...
- Player: How did throwing a backpack make you fall?
- Dead Drow: Mushrooms... disappear... guessed wrong...
- Player: How did throwing a backpack make you fall?
Player: Did you have any allies nearby?
- Dead Drow: Worked alone... better that way...
External Links
Underdark on the Forgotten Realms Wiki