Some dungeons are old strongholds abandoned by the folk who built them. Others are natural caves or weird lairs carved out by foul monsters. They attract evil cults, monster tribes, and reclusive creatures. Dungeons are also home to ancient treasures: coins, gems, magic items, and other valuables hidden away in the darkness, often guarded by traps or jealously kept by the monsters that have collected them.
When you set out to create a dungeon, think about its distinctive qualities. For example, a dungeon that serves as a hobgoblin stronghold has a different quality from an ancient temple inhabited by yuan-ti. This section lays out a process for creating a dungeon and bringing it to life.
You can use the Dungeon Location table to determine the locale of your dungeon. You can roll on the table or choose an entry that inspires you.
| Dungeon Location | Exotic Location | |||
| d100 | Location | d20 | Location | |
| 01-04 | A building in a city | 1 | Among the branches of a tree | |
| 05-08 | Catacombs or sewers beneath a city | 2 | Around a geyser | |
| 09-12 | Beneath a farmhouse | 3 | Behind a waterfall | |
| 13-16 | Beneath a graveyard | 4 | Buried in an avalanche | |
| 17-22 | Beneath a ruined castle | 5 | Buried in a sandstorm | |
| 23-26 | Beneath a ruined city | 6 | Buried in volcanic ash | |
| 27-30 | Beneath a temple | 7 | Castle or structure sunken in a swamp | |
| 31-34 | In a chasm | 8 | Castle or structure at the bottom of a sinkhole | |
| 35-38 | In a cliff face | 9 | Floating on the sea | |
| 39-42 | In a desert | 10 | In a meteorite | |
| 43-46 | In a forest | 11 | On a demiplane or in a pocket dimension | |
| 47-50 | In a glacier | 12 | In an area devastated by a magical catastrophe | |
| 51-54 | In a gorge | 13 | On a cloud | |
| 55-58 | In a jungle | 14 | In the Feywild | |
| 59-62 | In a mountain pass | 15 | In the Shadowfell | |
| 63-66 | In a swamp | 16 | On an island in an underground sea | |
| 67-70 | Beneath or on top of a mesa | 17 | In a volcano | |
| 71-74 | In sea caves | 18 | On the back of a Gargantuan living creature | |
| 75-78 | In several connected mesas | 19 | Sealed inside a magical dome of force | |
| 79-82 | On a mountain peak | 20 | Inside a Mordenkainen's magnificent mansion | |
| 83-86 | On a promontory | |||
| 87-90 | On an island | |||
| 91-95 | Underwater | |||
| 96-100 | Roll on the Exotic Location Table | |||
A dungeon reflects its creators. A lost temple of the yuan-ti, choked by overgrown jungle plants, might feature ramps instead of stairs. Caverns carved by a beholder's disintegration eye ray have walls that are unnaturally smooth, and the beholder's lair might include vertical shafts connecting different levels. Amphibious monsters such as kuo-toa and aboleths use water to protect the innermost reaches of their lairs from air-breathing intruders.
Details bring a dungeon setting's personality to life. Great bearded faces might be carved on the doors of a dwarven stronghold and might be defaced by the gnolls who live there now. Spiderweb decorations, torture chambers, and slave pens might be common features in a vault built by drow, telling something about that location and its occupants.
The Dungeon Creator table includes creatures that typically build dungeons. You can choose a creator from the table or roll randomly, or choose some other dungeon builder appropriate for your campaign.
| Dungeon Creator | |
| d20 | Creator |
| 1 | Beholder |
| 2-4 | Cult or religious group. (Roll on the Cults and Religious Groups table to determine specifics) |
| 5-8 | Dwarves |
| 9 | Elves (including drow) |
| 10 | Giants |
| 11 | Hobgoblins |
| 12-15 | Humans. (Roll on the NPC Alignment and NPC Class tables to determine specifics) |
| 16 | Kuo-toa |
| 17 | Lich |
| 18 | Mind flayers |
| 19 | Yuan-ti |
| 20 | No creator (natural caverns) |
| Cults and Religions | |
| d20 | Cult or Religious Group |
| 1 | Demon-worshiping cult |
| 2 | Devil-worshiping cult |
| 3-4 | Elemental Air cult |
| 5-6 | Elemental Earth cult |
| 7-8 | Elemental Fire cult |
| 9-10 | Elemental Water cult |
| 11-15 | Worshipers of an evil deity |
| 16-17 | Worshipers of a good deity |
| 18-20 | Worshipers of a neutral deity |
| NPC Alignment | |
| d20 | Alignment |
| 1-2 | Lawful good |
| 3-4 | Neutral good |
| 5-6 | Chaotic good |
| 7-9 | Lawful neutral |
| 10-11 | Neutral |
| 12 | Chaotic neutral |
| 13-15 | Lawful evil |
| 16-18 | Neutral evil |
| 19-20 | Chaotic evil |
| NPC Class | |
| d20 | Class |
| 1 | Barbarian |
| 2 | Bard |
| 3-4 | Cleric |
| 5 | Druid |
| 6-7 | Fighter |
| 8 | Monk |
| 9 | Paladin |
| 10 | Ranger |
| 11-14 | Rogue |
| 15 | Sorcerer |
| 16 | Warlock |
| 17-20 | Wizard |
Except in the case of a natural cavern, a dungeon is crafted and inhabited for a specific purpose that influences its design and features. You can choose a purpose from the Dungeon Purpose table, roll one at random, or use your own ideas.
| Dungeon Purpose | |
| d20 | Creator |
| 1 | Death trap |
| 2-5 | Lair |
| 6 | Maze |
| 7-9 | Mine |
| 10 | Planar gate |
| 11-14 | Stronghold |
| 15-17 | Temple or shrine |
| 18-19 | Tomb |
| 20 | Treasure vault |
Death Trap. This dungeon is built to eliminate any creature that dares to enter it. A death trap might guard the treasure of an insane wizard, or it might be designed to lure adventurers to their demise for some nefarious purpose, such as to feed souls to a lich's phylactery.
Lair. A lair is a place where monsters live. Typical lairs include ruins and caves.
Maze. A maze is intended to deceive or confuse those who enter it. Some mazes are elaborate obstacles that protect treasure, while others are gauntlets for prisoners banished there to be hunted and devoured by the monsters within.
Mine. An abandoned mine can quickly become infested with monsters, while miners who delve too deep can break through into the Underdark.
Planar Gate. Dungeons built around planar portals are often transformed by the planar energy seeping out through those portals.
Stronghold. A stronghold dungeon provides a secure base of operations for villains and monsters. It is usually ruled by a powerful individual, such as a wizard, vampire, or dragon, and it is larger and more complex than a simple lair.
Temple or Shrine. This dungeon is consecrated to a deity or other planar entity. The entity's worshipers control the dungeon and conduct their rites there.
Tomb. Tombs are magnets for treasure hunters, as well as monsters that hunger for the bones of the dead.
Treasure Vault. Built to protect powerful magic items and great material wealth, treasure vault dungeons are heavily guarded by monsters and traps.
In most cases, the original architects of a dungeon are long gone, and the question of what happened to them can help shape the dungeon's current state.
The Dungeon History table notes key events that can transform a site from its original purpose into a dungeon for adventurers to explore. Particularly old dungeons can have a history that consists of multiple events, each of which transformed the site in some way.
| Dungeon History | |
| d20 | Creator |
| 1-3 | Abandoned by creators |
| 4 | Abandoned due to plague |
| 5-8 | Conquered by invaders |
| 9-10 | Creators destroyed by attacking raiders |
| 11 | Creators destroyed by discovery made within the site |
| 12 | Creators destroyed by internal conflict |
| 13 | Creators destroyed by magical catastrophe |
| 14-15 | Creators destroyed by natural disaster |
| 16 | Location cursed by the gods and shunned |
| 17-18 | Original creator still in control |
| 19 | Overrun by planar creatures |
| 20 | Site of a great miracle |
After a dungeon's creators depart, anyone or anything might move in. Intelligent monsters, mindless dungeon scavengers, predators and prey alike can be drawn to dungeons.
The monsters in a dungeon are more than a collection of random creatures that happen to live near one another. Fungi, vermin, scavengers, and predators can coexist in a complex ecology, alongside intelligent creatures who share living space through elaborate combinations of domination, negotiation, and bloodshed.
Characters might be able to sneak into a dungeon, ally with one faction, or play factions against each other to reduce the threat of the more powerful monsters. For example, in a dungeon inhabited by mind flayers and their goblinoid thralls, the adventurers might try to incite the goblins, hobgoblins, and bugbears to revolt against their illithid masters.
A dungeon is sometimes dominated by a single group of intelligent humanoids, whether a tribe of orcs that have taken over a cavern complex or a gang of trolls inhabiting an aboveground ruin. Other times, particularly in larger dungeons, multiple groups of creatures share space and compete for resources.
For example, orcs that dwell in the mines of a ruined dwarf citadel might skirmish constantly against the hobgoblins that hold the citadel's upper tiers. Mind flayers that have established a colony in the lowest levels of the mines could manipulate and dominate key hobgoblins in an attempt to wipe out the orcs. And all the while, a hidden cell of drow scouts watches and plots to slay the mind flayers, then enslave whatever creatures are left.
It's easy to think of a dungeon as a collection of encounters, with the adventurers kicking down door after door and killing whatever lies beyond. But the ebb and flow of power between groups in a dungeon provides plenty of opportunities for more subtle interaction. Dungeon denizens are used to striking unlikely alliances, and adventurers are a wild card that canny monsters seek to exploit.
Intelligent creatures in a dungeon have goals, whether as simple as short-term survival or as ambitious as claiming the entire dungeon as the first step in founding an empire. Such creatures might approach adventurers with an offer of alliance, hoping to prevent the characters from laying waste to their lair and to secure aid against their enemies. Bring the NPC leaders of such groups to life as described in chapter 4, fleshing out their personalities, goals, and ideals. Then use those elements to shape a response to the arrival of adventurers in their territory.
An inhabited dungeon has its own ecosystem. The creatures that live there need to eat, drink, breathe, and sleep, just as creatures in the wilderness do. Predators need to be able to seek prey, and intelligent creatures search for lairs offering the best combination of air, food, water, and security. Keep these factors in mind when designing a dungeon you want the players to believe in. If a dungeon doesn't have some internal logic to it, adventurers will find it difficult to make reasonable decisions within that environment.
For example, characters who find a pool of fresh water in a dungeon might make the logical assumption that many of the creatures inhabiting the dungeon come to that spot to drink. The adventurers might set an ambush at the pool. Likewise, locked doors-or even doors that require hands to open-can restrict the movement of some creatures. If all the doors in a dungeon are closed, the players might wonder how the carrion crawlers or stirges they repeatedly encounter manage to survive.
You might be inclined to increase the encounter difficulty as the adventurers descend deeper into the dungeon, as a way to keep the dungeon challenging as the characters gain levels or to ratchet up the tension. However, this approach can turn the dungeon into a grind. A better approach is to include encounters of varying difficulty throughout. The contrast between easy and hard encounters, as well as simple and complex encounters, encourages characters to vary their tactics and keeps the encounters from seeming too similar.
Every dungeon needs a map showing its layout. The dungeon's location, creator, purpose, history, and inhabitants should give you a starting point for designing your dungeon map. If you need further inspiration, you can find maps that have been made freely available for use on the Internet, or even use a map of a real-world location. Alternatively, you can borrow a map from a published adventure or randomly generate a dungeon complex using the tables presented in appendix A.
A dungeon can range in size from a few chambers in a ruined temple to a huge complex of rooms and passages extending hundreds of feet in all directions.
The adventurers' goal often lies as far from the dungeon entrance as possible, forcing characters to delve deeper underground or push farther into the heart of the complex.
A dungeon is most easily mapped on graph paper, with each square on the paper representing an area of 10 feet by 10 feet. (If you play with miniatures on a grid, you might prefer a scale where each square represents 5 feet, or you can subdivide your 10-foot grid into a 5-foot grid when you draw your maps for combat.) When you draw your map, keep the following points in mind:
If you need help creating a dungeon map from scratch, see Random Dungeons.
The atmosphere and physical characteristics of dungeons vary as widely as their origins. An old crypt might have stone walls and loose wooden doors, an odor of decay, and no light other than what adventurers bring with them. A volcanic lair might have smooth stone walls hollowed out by past eruptions, doors of magically reinforced brass, a smell of sulfur, and light provided by jets of flame in every hall and room.
Some dungeons have walls of masonry. Others have walls of solid rock, hewn with tools to give them a rough, chiseled look, or worn smooth by the passage of water or lava. An aboveground dungeon might be made of wood or composite materials.
Walls are sometimes adorned with murals, frescoes, bas-reliefs, and lighting fixtures such as sconces or torch brackets. A few even have secret doors built into them.
Dungeon doorways might be set within plain arches and lintels. They might be festooned with carvings of gargoyles or leering faces or engraved with sigils that reveal clues as to what lies beyond.
Stuck Doors. Dungeon doors often become stuck when not used frequently. Opening a stuck door requires a successful Strength Test. The d20 Test provides guidelines for setting the DC.
Locked Doors. Characters who don't have the key to a locked door can pick the lock with a successful Dexterity Test (doing so requires thieves' tools and proficiency in their use). They can also force the door with a successful Strength Test, smash the door to pieces by dealing enough damage to it, or use a Knock spell or similar magic. Statistics for Objects provides guidelines for setting the DCs and assigning statistics to doors and other objects.
Barred Doors. A barred door is similar to a locked door, except that there's no lock to pick, and the door can be opened normally from the barred side by using an action to lift the bar from its braces.
A secret door is crafted to blend into the wall that surrounds it. Sometimes faint cracks in the wall or scuff marks on the floor betray the secret door's presence.
Detecting a Secret Door. Use the characters' passive Wisdom (Perception) scores to determine whether anyone in the party notices a secret door without actively searching for it. Characters can also find a secret door by actively searching the location where the door is hidden and succeeding on a Wisdom (Perception) Test. To set an appropriate DC for the Test, see The d20 Test.
Opening a Secret Door. Once a secret door is detected, a successful Intelligence (Investigation) check might be required to determine how to open it if the opening mechanism isn't obvious. Set the DC according to the difficulty guidelines in The d20 Test.
If adventurers can't determine how to open a secret door, breaking it down is always an option. Treat it as a locked door made of the same material as the surrounding wall, and use the guidelines in Statistics for Objects to determine appropriate DCs or statistics.
A concealed door is a normal door that is hidden from view. A secret door is carefully crafted to blend into its surrounding surface, whereas a concealed door is most often hidden by mundane means. It might be covered by a tapestry, covered with plaster, or (in the case of a concealed trapdoor) hidden under a rug. Normally, no ability check is required to find a concealed door. A character need only look in the right place or take the right steps to reveal the door. However, you can use the characters' passive Wisdom (Perception) scores to determine whether any of them notices tracks or signs of a tapestry or rug having been recently disturbed.
A portcullis is a set of vertical bars made of wood or iron, reinforced with one or more horizontal bands. It blocks a passage or archway until it is raised up into the ceiling by a winch and chain. The main benefit of a portcullis is that it blocks a passage while still allowing guards to watch the area beyond and make ranged attacks or cast spells through it.
Winching a portcullis up or down requires an action. If a character can't reach the winch (usually because it is on the other side of the portcullis), lifting the portcullis or bending its bars far enough apart to pass through them requires a successful Strength Test. The DC of the Test depends on the size and weight of the portcullis or the thickness of its bars. To determine an appropriate DC, see Statistics for Objects.
Darkness is the default condition inside an underground complex or in the interior of aboveground ruins, but an inhabited dungeon might have light sources.
In subterranean settlements, even races that have darkvision use fire for warmth, cooking, and defense. But many creatures have no need of warmth or light. Adventurers must bring their own sources of light into dusty tombs where only undead stand guard, abandoned ruins teeming with predatory monsters and oozes, and natural caverns where sightless creatures hunt.
The light of a torch or lantern helps a character see over a short distance, but other creatures can see that light source from far away. Bright light in an environment of total darkness can be visible for miles, though a clear line of sight over such a distance is rare underground. Even so, adventurers using light sources in a dungeon often attract monsters, just as dungeon features that shed light (from phosphorescent fungi to the glow of magical portals) can draw adventurers' attention.
Subterranean tunnels and aboveground ruins are often enclosed spaces with little airflow. Though it's rare for a dungeon to be sealed so tightly that adventurers have trouble breathing, the atmosphere is often stifling and oppressive. What's more, odors linger in a dungeon and can be magnified by the stillness of the atmosphere.
A dungeon's enclosed geography helps channel sound. The groaning creak of an opening door can echo down hundreds of feet of passageway. Louder noises such as the clanging hammers of a forge or the din of battle can reverberate through an entire dungeon. Many creatures that live underground use such sounds as a way of locating prey, or go on alert at any sound of an adventuring party's intrusion.
The hazards described here are but a few examples of the environmental dangers found underground and in other dark places. Dungeon hazards are functionally similar to traps, which are described at the end of this chapter.
Detecting a Hazard. No ability check is required to spot a hazard unless it is hidden. A hazard that resembles something benign, such as a patch of slime or mold, can be correctly identified with a successful Intelligence (Nature) Test. Use the guidelines in The d20 Test to set an appropriate DC for any check made to spot or recognize a hazard.
Hazard Severity. To determine a hazard's deadliness relative to the characters, think of the hazard as a trap and compare the damage it deals with the party's level using the Damage Severity by Level table.
| Damage Severity by Level | |||
| Character Level | Moderate | Dangerous | Deadly |
| 1-4 | 5 (1d10) | 11 (2d10) | 22 (4d10) |
| 5-10 | 11 (2d10) | 22 (4d10) | 55 (10d10) |
| 11-16 | 22 (4d10) | 55 (10d10) | 99 (18d10) |
| 17-20 | 55 (10d10) | 99 (18d10) | 132 (24d10) |