Building a Hex Crawl
One of humanity’s defining impulses is exploration and discovery, and hex crawls primarily cater to that. Hex crawls are about going to new places and finding new things until you have explored and documented a previously undiscovered wilderness like you were Lewis and Clark but with manticores, and then broken into the homes of and subsequently massacred any native populations you find to be inconvenient like you were Andrew Jackson but with goblins. The difference between a hex crawl and a wilderness campaign is that a wilderness campaign places the emphasis firmly on lurking evils threatening to overwhelm civilization. If the status of other regions is unknown at all, this is mainly an issue of reconnaissance, with potential dangers lurking underneath a fog of war, dangers that can be assumed to eventually come to your house and eat your lunch.
A hex crawl places the emphasis on exploration. The wilderness may well be full of dangerous things, but those things aren’t particularly imperialistic and probably won’t become a problem for your homeland in the foreseeable future. You don’t explore to reveal threats, you explore because you like exploring. There might be some other quest involved – maybe you’re trying to recover artifacts stolen from your kingdom and scattered through the wilderness, or maybe you’re mapping the area for future settlement, or maybe you’re exploring a newly discovered wilderness to try and make allies amongst the locals and convince them to join your fantasy federation. Ultimately, though, players are exploring, and whatever the main plot is, it shouldn’t make them feel bad about sticking their nose into every hex on the map just to see what’s in there. In other words, that thing open world games do sometimes, where they set up the main plot as being a countdown to Armageddon and then set you loose in the map and you chase collectibles and unrelated side quests for five hours before you remember that whole “demonic invasion” thing? Don’t do that.
The Scope of a Hex Crawl
The process of traveling from one hex to another is a process. It can take 5-10 minutes, and it’s a lot of die rolling and assigning of roles and taking notes and may include a random encounter that will take up another fifteen or twenty minutes on top of that. You can cut down a lot on this by drastically oversimplifying the process, but you shouldn’t, partly because each step involved adds important options to travel that at some point your PCs will want to take advantage of (i.e. you can limit all hex travel to fixed speeds, but at some point PCs will want to get on a horse and ride through the night and there is no particularly good reason they shouldn’t be able to do that), but mostly because this process makes for some good winding down time between hex encounters/adventures.
The important corollary to this is that most hexes the party enters should have enough stuff in them to justify a 5-10 minute simmering down period afterwards. At least 70% of all hexes should contain, at minimum, a significant encounter that will hopefully take at least half an hour to resolve. The remainder should have at least some kind of feature or landmark to them just so that each hex has something to discover, even if it’s just an ancient wizard’s tower that is now completely, genuinely empty. And again: These kinds of things shouldn’t be more than 30% of the hex crawl maximum and preferably less than that. The party shouldn’t be spending more than a quarter of the session just walking places, even in a hex crawl where walking places is the selling point, so they should have a high probability that after going through the process of traveling from one hex to another, there will be something in that next hex.
This means that when you make a hexcrawl, you are committing yourself to creating quite a few encounters and adventures. A 6×6 hex crawl, about the minimum size before it starts to feel like exploring a prison cell, has 36 hexes. That means you need at least 26 encounters or adventures to shove into them, and you’ll probably want at least one urbancrawl town somewhere to use as home base. That urbancrawl is going to probably be at least two or three adventures (or adventures’ worth of material, depending on how you distribute it) of material. The average published adventure has an average of about three main encounters in it, which means that a 6×6 hexcrawl has approximately (counting three urbancrawl adventures) a dozen adventures’ worth of material. That’s a full campaign, and it’s also the minimum size of a hex crawl, so definitely think carefully before making your hex crawl any bigger. If you use 30 mile hexes (which can definitely seem like an odd size at first glance, but we recommend it for reasons we’ll get into later), a 6×6 hex crawl is about the size of the entire island of Ireland, the modern nation of Austria, the state of South Carolina, or the Japanese island of Hokkaido. In other words, it’s the size of a respectable medieval kingdom and thus perfectly suited for a complete D&D campaign from low to mid levels (high levels usually go to some lower plane to stab Satan in the face, or you go underwater to fight the sahuagin queen, or something).
You can get larger than 6×6, much larger if you’re particularly ambitious. A 6×6 hex crawl is large enough for the average published campaign, but the average published campaign lasts less than a year in play (5e releases them about as fast as the average group can complete them, and their release schedule is twice annually). An 8×8 hex crawl is about the size of Greece, the nations of England and Wales combined, the state of Illinois, or the Liaoning province of China. This will require at least 15 adventures’ worth of content in the hexes, and if you still have only one major city, close to 20 adventures’ worth total, which is close to a year’s worth of play. Not-England is the setting for quite a few medieval fantasy stories, so this is also a pretty defensible size, though not recommended for new players.
If you want to add in Scotland for the entire island of Great Britain, you will need a 10×10, or 21 adventures in the hexes, and you’re also probably going to want at least two cities at this point, probably three, which means you’re looking at over 30 adventures, which is definitely going to take at least a year to play, and we haven’t even added in Ireland yet. We’re far behind the size of Germany or Japan, both in the neighborhood of 13×13, or 119 encounters plus multiple urbancrawls for a total of 50+ adventures, which can take the better part of two years. It’s even further behind France, a 16×16, 54 adventures and you’ll probably want a minimum of four major cities for 70+ adventures’ worth of material, putting us in the neighborhood of three years of content for a weekly group that moves fairly quick. So, we’re starting to see the limits of a hex crawl here.
Taking this to a crazy extreme just for fun, covering all of China would be a 64×64, and while modern China is much larger than the ground covered by Romance of the Three Kingdoms, if you wanted to add in the ground covered by Journey to the West (and the other two of the Four Classics while you’re at it, but those both take place in the same area as RotTK) that would actually be slightly larger than what the PRC covers and would take about 30 years to clear if you played 45 times per year (i.e. a weekly game with occasional canceled games). Want Europe and the Middle-East to play fantasy Crusader Kings? You’re now at the unimaginably large 100×100 hex crawl, and clearing a hex crawl of that size properly packed with encounters would take actual centuries. Just creating such a crawl would require either tons of crowdsourcing or else would have to be a generational project, and that’s with us using larger than normal hexes. If you decide to convert to six-mile hexes, the number of encounters needed to fill in a hex crawl the size of [region] is even bigger (which is not why we recommend thirty-mile hexes, but it is a nice bonus).
Going larger than 10×10 is generally not advised and even a 6×6 is plenty big for most purposes. It is theoretically plausible to go as large as 16×16 but it will be monumental both in creating and running it, so it is recommended only for dedicated groups who want to play very long term exploration campaigns. Remember, there’s nothing stopping you from stringing different campaign types together if you’d like to keep playing the same characters, so even if you do want a very long term campaign, it still might be wiser to run an 8×8 hex crawl and then have the characters move to a different location where they have a wilderness campaign or an intrigue campaign or whatever. If you really want to explore a France’s worth of hexes, though, 16×16 is the upper limit of reasonable doability, but it is reasonably doable if you’re committed.
What kind of encounters or adventures do you put in a hex crawl? Hexes can obviously contain complete adventures and you should have at least a few of those lying around. Multi-level dungeons and mysteries are by far the most obvious and easiest to do, while wilderness journeys are generally speaking incongruous with the hex crawl, but not always. While a multi-day journey makes little sense in the confines of a single hex, the wilderness journey mechanics work just as well for a short journey through an area densely packed with danger, for example, if there’s a hidden temple in a forest thick with dark fey, you could use a wilderness journey adventure for getting through the forest to the temple. Mass combats are also a strange sort of adventure to have in a hex crawl because the party might discover the adventure, walk away from it for weeks or months, then come back, and it’s odd that the military situation hasn’t shifted at all. Some hexes might indeed be home to some kind of military stalemate or cold war that won’t change until the players arrive to tip the balance one way or the other, and others might simply be home to a large army of enemy monsters, such that clearing the hex requires players to gather up an army of their own and drive them off.
Complete adventures are big and take a lot of time both to design and play, though, and there’s no reason to make all 70% (or preferably more) of your significant hex encounters include them. All that a hex encounter absolutely needs is a hook, a bit of build up, and then an encounter for pay-off. As such, it’s acceptable for a hex encounter to be a simple two-scene mystery, in which you have a hook that immediately draws the players’ attention (the burned out remains of a caravan, for example), three clues that all point towards the same scene, and then in that scene there is a confrontation with whoever sacked the caravan, some goblins in a cave or whatever. One-page dungeons with just four or five encounters make for good hex fodder (Matt Colville has a few videos on how to make a one-page dungeon, and that general formula can be repeated a couple of times without getting old so long as you don’t put any two of them immediately adjacent to one another, so players don’t get them one right after another).
Once you get used to designing these relatively brief encounters, it becomes easy. Then the trick is to come up with enough new ideas that it doesn’t become stale. Any adventures you’ve had fun running or playing can probably be converted to work as a hex encounter. Adventure paths can often be chopped up and have their pieces planted into a hex crawl like a macabre garden. Generic dungeons like the Temple of Elemental Evil or the Keep on the Borderlands can be dropped in practically any setting. Material from entirely different genres, like the Warhammer 40k or Warhammer Fantasy RPGs, the Star Wars RPGs, or Call of Cthulhu can often be adapted.
Material from totally different media can provide the ideas needed to create encounters or adventures from scratch. Mine books, movies, and games for plothooks or setting ideas. Bioshock is about an underwater society gone mad due to the corrosive psychological effects of superpower granting drugs, which is easily fodder for a D&D dungeon crawl. The Terminator is about a nigh-invincible assassin sent to kill a hapless victim, one so powerful that he most be evaded and worn down over multiple encounters rather than simply confronted and killed. Alien is about being stalked by a monster that will 100% kill you if it catches you alone and unawares, but will be more vulnerable if confronted by a large, prepared group, making it a game of trying to find the monster without being separated and picked off. The sequel Aliens is about those same monsters forgoing the whole “hidden stalker” thing and just Zerg rushing the party through the air ducts.
And when you inevitably run out of ideas or energy for the project, just give it a few weeks to simmer and then come back to it. Hex crawls of any appreciable size will take a long time to complete, so don’t expect to get it all done in a week between session zero and the start of the campaign. It’s surely possible to hammer out three shoddy encounters a day and jam them all into a 6×6 hex crawl, but it won’t be any fun.
The hex crawl is also going to require a random encounter table. This table should be a d100, but you’re going to roll it on each and every hex the party enters, so don’t be afraid to stock large parts of it with “nothing happens.” Each major region of the hexcrawl should have its own random encounter table, with each random encounter table covering no more than about 40 hexes. This means that it’s fine if your 6×6 hexcrawl has only a single encounter table, but an 8×8 should have at least two and a 10×10 should have at least three. “Regions” don’t necessarily have to be contiguous. You might have a plains table, a hills table, and a forests table for something resembling medieval Britain or France, and none of those regions would be particularly contiguous. Splitting things up by terrain often makes more sense than splitting them up by political boundaries, but sometimes it makes a big difference whether it’s the Knights of Solamnia or the Knights of Neraka who are patrolling the region. Pick whichever is more appropriate for the hex crawl you’re running.