How to generate a dungeon map

Exploring the many ways to make a randomly generated map for your next dungeon crawl using dice and cards

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What is a dungeon?

It’s worth taking a moment to explain what I mean by “dungeon” in this context, because it’s not always a dark, damp place under a fantasy world castle.

For me, dungeon is a generic term for an explorable, often hostile environment designed as an obstacle for players to encounter. It is the part of the game that exists to facilitate the things that make a dungeon crawl good:

1. Exploration and discovery

2. Risk, player agency, and meaningful choices

3. Engaging progression system

The poll with the article asked, “Which dungeon crawler element is most important?” Of the five options which included character progression, combat, loot, puzzles & environmental challenges, and replayability, it was puzzles & environmental challenges that received the most votes (31%):

Poll results from last week’s article (N=66)

Perhaps unsurprisingly, it is the dungeon itself that players feel is the most important part of the dungeon crawl!¹

And while that dungeon certainly can be made of stone walls deep underground and stocked with goblins, traps, and undead skeletons, dungeons in this sense can also have many other settings: spaceships, mansions, wilderness areas, and submarines.

Any place I say “dungeon” in this article, remember that it doesn’t need to be a classic fantasy dungeon. I consider Nemesis, Hellboy: The Board Game, and Cthulhu: Death May Die to all be dungeon crawlers.

Dungeon generation methods

Particularly for solo play, being able to randomly generate a dungeon on the fly is important. In the poll, randomization and replayability received the second highest amount of votes (22%).

Let’s look at a few ways to generate dungeons and dungeon maps:

1. Dice roll rooms and connections

Dark Fort

Rolling dice and using a table to look up the results is one of the most common dungeon generation methods. It’s used in Dark Fort to create a surprisingly thematic, if chaotic, dungeon. Roll 1d6 for the room contents (e.g. pit trap), 2d6 for the room shape (e.g. square or oval), and 1d4 for the number of doors/exits. This creates an ever expanding and completely random dungeon of connected rooms.

Variations might include pre-defined dungeon segments (similar to geomorphs) in place of a text-based table. Delving in the Dark by Logen Nein does this with a 2d6 Segment Chart combined with additional tables for dressing, oddities, encounters, door types, treasures, and traps.

Wallet Dungeons by Awkward Turtle uses a handful of d6s arranged in 3D space to create a dungeon with elevation. Each die value can only touch a certain number of other dice, creating a sort of puzzle to solve. Dice can be stacked with each neighboring die contributing to the room type. And it all fits on a business card!

• Pros:

  • Easy to implement and design

  • Relatively quick to use

  • Requires very little space and no special components

• Cons:

  • Excessive number of dice rolls can become tedious²

  • Chance of repeating the same rooms too many times

  • Possibility of dead ends ending the dungeon too early

2. Card-driven rooms

52 Card Dungeon

Instead of dice, a standard deck of playing cards can be used to randomly generate rooms and their contents.

52 Card Dungeon by Sam Armstrong begins with a single card (Joker) as the dungeon entrance, the first room of the dungeon. Each card drawn indicates how many cards (i.e. rooms) will be drawn next and where to place them. For example, drawing a 4 will cause cards to be added to the left and right of the current room. This process can continue until the dungeon is as large as necessary. There is almost zero chance of hitting premature dead ends.³

My Little Dungeon Generator by Dodocahedron Games uses an interesting system where the rank of the cards is used to create squared-off numbers. These numbers are then pushed together to form the outline of the dungeon rooms, creating a dungeon of rooms packed next to each other rather than separated by long corridors.

• Pros:

  • Cards store more information than a single dice roll

  • Cards have a memory, meaning no repeated results

• Cons:

  • Requires a deck of cards vs. simply dice

  • Potentially more design work (52 items vs. D6 or D66 items)

  • Might still have to roll dice in addition to the cards (e.g. for exits)

3. Card grid exploration

The Carta SRD by Peach Garden Games is a good example of grid exploration:

The base idea is that players lay cards out in a grid, and then turn them over one at a time, exploring prompts and mechanics as they do. The game is a sort of boardgame / storygame hybrid, where players explore journaling prompts by physically moving their marker from card to card and looking up the results.

As written, this method allows free movement in any orthogonal direction during play, which might be too “open” for a dungeon. It would be easy, however, to restrict movement based on card value or other method.

I originally wrote about the Carta SRD and player agency, but beyond the simple forms of the game system, I think it could be a really interesting dungeon generation method.

• Pros:

  • Uses cards with memory to avoid repeats

  • Doesn’t require specialized cards (poker cards work)

  • Enforces a grid where that would make sense (e.g. a house or building)

• Cons:

  • May need to develop way to restrict movement (i.e. add walls)

  • Large dungeons will require a lot of table space

  • Uses a fixed grid which potentially limits loops and connections

4. Custom cards and dice

TSR Dungeon Geomorphs

The last category uses custom or specialized components to create randomly generated dungeons. This usually requires either making a purchase or doing some at-home crafting and “print and play” work.

I’ve written about dungeon geomorphs previously — modular pieces of a terrain or map that is used to create larger random or procedurally generated maps. They’ve been around at least as far back as the TSR Dungeon Geomorphs designed by Gary Gygax and published in 1976. Newer sets include:

• Geomorphs by Dyson Logos (with links to others)

• Dungeon Geomorphs 2013 by Majcher Arcana

• Dungeon Explore Card Deck by Knights of Vasteel

• Starship Geomorphs by Robert Pearce

The Dungenerator and Axebane’s Deck of Many Dungeons are two other popular examples. DungeonMorphs by Inkwell Ideas takes this a step further with actual dice with dungeon segments on each side.⁴

• Pros:

  • Creates interesting dungeons with unique rooms

  • Prevents repeats and too many dead ends

  • Prevents the need to manually draw each dungeon segment

• Cons:

  • Often requires a purchase and/or custom components

  • Can’t easily be incorporated into your own commercial game designs

  • Can be restricted to the provided dungeon segments and theme

Conclusion

This would not be a very interesting dungeon.

Some things to think about:

• Choose the right method: Which method is the right one? The one that works best for your design and that fits the kinds of fun you want your players to have. Take the time to consider all of your options.

• Consider edge cases: It might be unlikely that your player will roll a 1 three times in a row (0.463% or about 1 in 216), it can happen. If your starting room has three entrances, they will be stuck and the adventure comes to a premature end.

• Consider theme and mechanisms: A sprawling mess of rooms connected by corridors might make sense in a dark fantasy game like Dark Fort, but would make less sense in a realistic, modern setting. Think about how the dungeon generation method supports the theme and setting of your game.

Which dungeon generation method is your favorite? Which methods did I miss that I should have included?

— E.P. 💀

P.S. Curse items and sell them to unsuspecting customers in Caveat Emptor by Exeunt Press. Available as PDF and in print.

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1. I find it fascinating that “combat encounters” was at the low end of the poll with just 15% of the votes. Almost all dungeon crawls rely on combat as a core mechanism, but they certainly don’t have to. I’m hoping to write about this in the future, so if you have any tips/examples for dungeon crawlers with low/no combat, please leave a comment!

2. I think I’m more sensitive to “too many dice rolls” than most people, so take this for what it’s worth. Some people never get tired of rolling the shiny math rocks, but I do if it’s (a) many in a row and (b) does not involve any player agency/choice.

3. 52 Card Dungeon also has bosses, floor modifiers, combat rooms, encounters, traps, and treasure included. It packs a lot into its 20 pages.

4. There is a different (?) set of dice also called DungeonMorphs. Perhaps a popular name?