Dungeons & Dragons: 8 Largest Dungeons In Fifth Edition (2024)

One of the most important aspects of adventuring in is the dungeons themselves, which are mostly tools for players to use their many class features and magic items while looting for more treasure. Although any interior location can be labeled as a 'dungeon,' the best ones take you on an extensive and dangerous journey.

Most of the largest dungeons in Fifth Edition D&D have been relatively scaled-down compared to previous editions to make room for role-playing and traveling mechanics, but can still outrank even the largest dungeons ever drawn. And, as always, they are filled to the brim with gold pieces and magic items.

8 Frost Giant Stronghold

Tales From The Yawning Portal

The second in a line of giant strongholds you can conquer in the Against the Giants adventure, this fortress is guarded by Jarl Grugnur and his army of frost giants and various ice-themed monsters. Despite having few outcomes that do not result in death, you are tasked with lowering their numbers and ending their threat to the kingdom.

While this dungeon has fewer areas compared to most of the largest dungeons, the areas that you can explore are often quite vast and can be hundreds of feet across with a direct line of sight. Being lived in by giants also makes the living spaces larger than life, which is bad news for gnomes and halflings.

7 Lizardfolk Lair

Ghosts Of Saltmarsh

Although technically one of many types of lairs home to lizardfolk, this lizardfolk lair sits on the outskirts of Saltmarsh and operates with a local group of smugglers to acquire durable and sharp weaponry. It's up to the players to rid these lizardfolk of their stash or eliminate the tribe altogether.

While not the largest dungeon in 5e, this lizardfolk lair is surprisingly dense and contains over 50 areas, most of which contain some sort of conflict or challenge. Because there are so many unique characters and room interactions, it makes this dungeon feel much bigger than it already is.

6 The Sunless Citadel

Tales From The Yawning Portal

An ancient fortress now fallen into ruin, the Sunless Citadel has been taken over by various monsters and an evil druid, intent on using the power of the Gulthias tree for his nefarious ends. This dungeon is meant for first level players, which is surprising considering just how much danger there is to find.

The Sunless Citadel is separated into four different sections with over 50 areas spread throughout, and littered with both weak and strong enemies. However, compared to most of the larger dungeons, the Sunless Citadel allows for plenty of passive solutions to conflict and unique interactions to major threats.

5 Khundrukar

Tales From The Yawning Portal

Once a dwarven stronghold housing great treasure and works of steel and art, Khundrukar has since fallen to tribes of orcs and monsters that have claimed it as their home. Although a small community of duergar still call it their home deep inside the mountain, it is otherwise lost.

Like any good dungeon delver, you are tasked with looting the ancient city in search of ancient weapons that could have only been forged by the ancient duergar who ruled here. Despite being a 3-5 level adventure, it is surprisingly long, and takes you across various levels containing over 50 areas in total.

4 The Hall Of The Fire Giant King

Tales From The Yawning Portal

In the final location of the Against the Giants adventure, you can explore the sweltering halls of King Snurre Iron Belly. Rather than finding a hidden item or retrieving a captive, you are expected to raid the hall and slaughter any giant who stands in your way until you have your audience with the king.

Luckily for King Snurre, his hall is massive, and not only contains two levels but has a cave system beneath it housing a red dragon and a treasure pile worth over 15,000 gold pieces in coin alone. Also, being a giant's domain, many of the areas are doubled in size, allowing you to live your Jack and the Flaming Beanstalk adventure.

3 Castle Ravenloft

Curse Of Strahd

The home of the immortal vampire, Count Strahd von Zarovich, Castle Ravenloft is part castle and part mausoleum, filled with rooms only an evil vampire could have thought of. In Curse of Strahd, there are multiple opportunities to visit the castle and is where you'll ultimately have your final showdown against Strahd.

To keep track of the enormous castle, there are 12 total maps to contain the 80 plus areas. The area beneath the castle alone is a fully sized dungeon with 40 crypts, each containing unique treasure, traps, and backstories for the people buried there.

2 The Doomvault

Tales From The Yawning Portal

The Doomvault is a hidden training ground meant to initiate and test Thayan red wizards. As a part of a complicated history involving magic portals and an ancient archmage, the Doomvault's most important feature is the phylactery vault, which houses the life essences of the lich, Szass Tam, and his most powerful servants.

In the Dead in Thay adventure, you are tasked with finding and destroying these phylacteries while traversing the unpredictable and dangerous Doomvault. Separated into nine sectors and over 100 areas, the massive vault is expected to level up your character from 9th to 11th by the time you've finished.

1 The Undermountain

Waterdeep: Dungeon of the Mad Mage

Considered the largest dungeon in the existence of Faerûn, the Undermountain is more accurately described as many dungeons stacked on top of each other, each level being more dangerous than the last. One entrance to the Undermountain can be found in the Yawning Portal, a famous tavern that hosts would-be dungeon delvers.

In the Dungeon of the Mad Mage adventure, you can explore all 23 layers, with each layer acting as a full-sized dungeon. After having leveled up twelve times and finally reaching the lowest level of the Undermountain, you get to meet the mad mage, Halaster, who might allow you to become his new apprentice should you survive the trials ahead.