Dungeon Generation

A procedure for generating dungeons. Where results don’t make sense or aren’t appropriate or pleasing, adjust as you see fit. This procedure provides only a skeleton. You must provide the meat yourself.

Beneath The Cobbles provides an example of a dungeon generated using this method and stocked using the treasure tables.

The Procedure

  1. Choose dungeon size.
    1. (Optional) Choose Dungeon Level if using this procedure in conjunction with A Dungeon Game’s treasure tables.
  2. Generate and number your rooms.
  3. Generate exits and room connections.
  4. Stock your dungeon.
  5. Write.

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Dungeon Size

For the purposes of using these generation tools and distributing treasure, dungeons comes in three sizes:

  • Small. 4 to 15 rooms. Can be explored in around 4 hours of play. Parties may explore this dungeon in one delve, only returning to the surface when they have achieved their goals.
  • Medium. 16 to 24 rooms. Can be explored in around 8 hours of play. Parties might camp just outside the dungeon, or set up a safe place to rest for the night inside. Food and resources might be tested.
  • Large. 25+ rooms. Will take many sessions to explore. Parties may leave and return multiple times, and resource management will be important. 1

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One of the classic modes of play revolves around the megadungeon, a vast complex of hundreds of rooms and potentially dozens of levels. Megadungeons generally form the basis of an entire campaign, with most of your play occurring in the dungeon over many delves.

These tables can easily be used to construct a megadungeon, generating discrete chunks of different sizes and connecting them together to form one larger complex.

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Dungeon Level

The term level” when applied to dungeons refers to the approximate Adventurer Level 2 of the characters assumed to be exploring the space. As parties will often be formed of characters of varying levels of experience, you should try not to worry about this too much. These are simply guidelines rather than strict rules - the idea of balance’ is something that isn’t a concern in A Dungeon Game, as players are expected to explore with caution and not treat every encounter with a denizen of the dungeon as an opportunity for violence.

Select the dungeon level that fits your needs, and then find the row on the treasure tables that corresponds to your chosen Size and Level.

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Level vs. Floor

A dungeon may be split over several floors. In traditional modes of play, each floor of the dungeon roughly corresponds to an equivalent level - that is, the first floor of the dungeon where characters initially enter (for the most part - see Non-Linear Dungeons for more on that) will be built with 1st level characters in mind, the next floor will be built with 2nd level characters in mind, and so on.

A Dungeon Game is less concerned with this clear divide between floors of the dungeon. It’s still true that in general large dungeons should become more dangerous as one moves deeper into them, and it would be unusual to find a level 1 section of the dungeon directly bordering a much higher level section, but you should feel free to assign dungeon levels to areas as you see fit and to allow sections of the dungeon of a specific level to contain multiple floors. Adding verticality to dungeons always makes for a much more interesting exploration experience!

Dungeons smaller than 4 rooms will tend not to contain large treasure hoards, and instead should be stocked with individual treasure appropriate to their occupants and purpose. As with everything, use your best judgement and build something that fits your game. If you want to place a large hoard at the end of a 3 room dungeon, that is entirely your prerogative.

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Room Generation

  • Gather six-sided dice equal to the number of rooms required.
  • Drop the dice on a sheet of paper.
  • Record the number shown on each die where it lands.
  • For each number, generate a corresponding room size and shape. For results of 1-3 roll on Table A. For 4-6, Table B.
  • Number your rooms, starting at 1 with the entrance to the dungeon.
1d20 Table A Table B
1-2 Square, 20’ x 20’ Square, 10’ x 10’
3-4 Square, 20’ x 20’ Square, 15’ x 15’
5-6 Square, 30’ x 30’ Square, 25’ x 25’
7-8 Square, 40’ x 40’ Square, 35’ x 35’
9-10 Rectangular, 20’ x 30’ Rectangular, 10’ x 20’
11-13 Rectangular, 20’ x 30’ Rectangular, 20’ x 30’
14-16 Rectangular, 30’ x 50’ Rectangular, 20’ x 40’
17-19 Rectangular, 40’ x 60’ Rectangular, 30’ x 40’
20 Unusual shape and size (roll on tables below) Unusual shape and size (roll on tables below)
1d6 Unusual Shape
1 Circular. (Roll 2d6: 2-6 has a pool; 7-9 has a well; 8-10 has a shaft; 11-12 has no special feature).
2 Triangular
3 Odd-shaped (draw any shape your desire or that fits the map)
4 Hexagonal
5 Octagonal
6 Cave; irregular shape
2d6 Size of Unusual Room
2-3 Approx. 500 square feet
4-6 Approx 900 square feet
7-9 Approx 1300 square feet
10-11 Approx 2000 square feet
12 Approx 2000 square feet plus roll again and add the result

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Exits and Connections

For each room roll 2d6 on the following table to generate a number of exits. For Room 1, place an additional exit manually before rolling. This is your dungeon entrance. Exits may be doors, open passages, or anything else you desire.

2d6 # Of Exits
2-3 1
4-5 2
6-7 3
8-10 1d3
11 0 (No visible exits. For each 10’ of wall roll 1d6. On a 1, a secret door is present.)
12 1d6

You may roll for the location of exits or place them as desired.

1d20 Exit Location
1-4 North wall
5-9 East wall
10-14 South wall
15-19 West wall
20 1d6: 1-4 Floor, 5-6 Ceiling

Roll on the following table for each exit in your dungeon. Begin in room 1, then move to the final room, then back to room 2, and so on, moving back and forth until all doors have been accounted for. All exits are assumed to be doors, but you may decide to instead roll for the Exit Type (below).

For dungeons with only one level:

2d6 Behind the door
2-3 Dead end passage 2d20’ in length.
4-6 False door, trapped
7-10 Roll 1dX (where X is the number of rooms in the dungeon). A passage links to that room.
11 False door, alarmed
12 Exit to surface

For dungeons with multiple levels:

2d6 Behind the door
2 Dead end passage 2d20’ in length.
3-5 False door (1d6: 1-3 trapped, 4-6 alarmed)
6-8 Roll 1dX (where X is the number of rooms in the dungeon). A passage links to that room.
9-11 Egress to another floor (1d6: 1 - stairs up, 2 - stairs down, 3 - shaft up, 4 - shaft down, 5 - slope down, 6 - elevator down)
12 Exit to surface
1d6 Exit Type
1 Door, unlocked
2 Door, locked
3 Open passageway
4 Iron gate
5 Portcullis
6 Glass window

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Dungeon Stocking

Use the following tables to generate the contents of your dungeon, rolling for each room in turn and noting down the result. The first table is for dungeon with multiple floors and will provide connections between levels. The second table is for single-floor dungeons.

Make use of the Treasure Tables to generate a hoard for the dungeon. Where these tables give a result of Treasure”, place some or all of the hoard in that room.

2d6 Table 1: Room Contents for Multi-Floor Dungeons
2 Trap & Treasure
3 Trap
4 Monster & Treasure
5 Monster
6 Stairs/Egress
7/8/9 Empty Room
10 Monster & Treasure
11 Treasure
12 Special
2d6 Table 2: Room Contents for Single Floor Dungeons
2 Trap & Treasure
3 Trap
4 Monster & Treasure
5/6 Monster
7/8/9 Empty Room
10 Monster & Treasure
11 Treasure
12 Special
2d6 Method of Egress
1-3 Chimney
4-7 Stairs
8-10 Chute/slide
11-12 Ravine/cliff/collapsed floor
2d6 Length of Egress
2-3 Down three floors
4-5 Down two floors
6-9 Down one floor
10 Up one floor
11 Up 3d6x10 feet; ends in dead end
12 Down 3d6x10 feet; ends in dead end

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Write Room Keys

You may wish to renumber your rooms now that you can see the layout of the dungeon so that they make more sense.

Then, using the notes from the stocking procedure, write your rooms.

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  1. As with everything, these are guidelines - especially the time estimates! I have personally found that the 10 minute dungeon turn roughly maps to 10 minutes of real play, i.e. if my group plays for an hour, we will generally explore somewhere around six rooms. This is entirely a matter of the play style of individual groups, and your experience may well vary. This is fine, and the more you play the more you’ll get a sense for how big or small your dungeons should be to fit comfortably into your sessions.↩︎

  2. See the Advancement chapter of A Dungeon Game for details.↩︎