GM’s Guide: Crawling Hexes

Crawling Hexes

So, you’ve got a bunch of encounters and adventures out there in the big, unexplored wilderness, you’ve set your party down in their starting hex, and now they would like to go to an adjacent hex. How do?

Traveling from one hex to another is a ten step process, although many of the steps are just “check to see if X is happening,” where the answer will usually be no. The checklist is below, and it’s recommended that you print it out and use it as an actual checklist. If you have a DM’s screen and any part of that screen is not already occupied with information you actually use regularly, tape the hex crawl checklist over that part of the DM’s screen for as long as you’re running a hex crawl. Otherwise, just make sure it’s as handy as your monster stats or your adventure outlines. This checklist is optimized for speedy resolution, trying to remember all ten steps off the top of your head will slow things down and often doing them out of order will require redoing steps you did earlier than you were supposed to. The process of traveling from one hex to another is meant to be the first stage of building tension towards the climax of whatever encounter is found in the next hex, but doing it from memory can often be frustrating instead.

1. Assign roles
2. Choose bearing and pace.
3. Record speed loss from travel.
4. Roll Constitution saves.
5. The party guide makes a navigation check.
6. Mark off supplies and/or hunter rolls Survival.
7. Enter the new hex (if the party has enough speed to make it today).
8. The guide rolls Stealth (if sneaking).
9. Roll for random encounter.
10. The spotter rolls Perception to find the hex encounter.

Step 1: Assign Roles

There are three roles in a hex crawl. Attempting to do two or more of the roles grants disadvantage on all checks related to the roles, so it’s worth splitting them up. The guide is in charge of making navigation checks, which can be either Survival, Investigation, or History. History is rolled at disadvantage, however, because knowing the terrain in theory is very different from knowing it in practice, so preferably the guide will have either high Survival or high Investigation. The spotter needs high Perception, and the hunter needs high Survival. Party members with no role assigned may assist party members with their role checks, granting advantage on the check, however party members with a roll assigned may not assist other party members with their roles.

Step 2: Choose Bearing and Pace

Once roles are assigned, the party chooses a bearing and pace. Bearing is pretty straightforward. Every hex has six faces in the same cardinal direction. If you have true columns, these directions are north, northeast, southeast, south, southwest, and northwest. The party picks one of these directions to head in.

The pace the party can move at determines their speed. Each hex is thirty miles across and requires 30 speed to cross by default, however some hexes require more than 30 speed to exit (see step 3 for details). A creature’s strategic speed is equal to their tactical speed in feet, i.e. most medium creatures move 30 miles per day, some move 35, etc. A party moves at the speed of its slowest member, but anyone riding a mount may use the mount’s speed instead of their own.

A party moving at a slow pace gets advantage on either their Stealth check to avoid detection in step 8 or to their Perception check to find the hex encounter in step 10, but not both, they get advantage on their Survival check to hunt in step 6 no matter what, and their movement speed is multiplied by 0.75. On the other hand, a party that’s moving at a fast speed gets disadvantage on their Survival check in step 6 and their Perception check in step 10, can’t roll Stealth in step 8 at all, and their movement speed is multiplied by 1.25.

Step 3: Record Speed Loss From Travel

Now that you have your pace set, you know what the party’s speed is. Every time the party exits a hex, their speed is reduced by an amount depending on what kind of hex they’re leaving. Tangled jungles require more speed to exit than open plains, roads make things much faster, and so on. If the party has some leftover speed and can’t quite exit a hex, then mark down how much speed they’ve spent on it today and they can add more on the following day. It may take the party several days to exit particularly treacherous terrain. If the party is moving with fly speed instead of land speed, they treat all hexes as being plains hexes, regardless of their actual terrain, however they do not benefit from roads (air currents and the like slow down long distance air travel just like bumps and gullies do on the ground, but cannot be paved over).

Terrain	Speed cost to exit
Grassland	30
Blue Water	30*
Coastal	40
Desert	40
Arctic	50
Hills	50
Forest	60
Underdark	70
Mountain	90
Swamp	100
+Road	x0.5
+Water Crossing	x1.5**

*Blue water hexes can only be crossed by creatures with a swim or fly speed. Creatures who cannot breathe underwater may not end their movement for the day on a blue water hex (unless the hex has some kind of small speck of land to rest upon, although most hexes with islands in them are coastal rather than blue water). If forced to do so because they lack enough speed to exit the hex, they drown.

**Creatures with a swim speed or some other means of crossing rivers, straits, etc. etc. without looking for a ford may ignore the speed cost multiplier for a water crossing. Finding some way to cross a river with a grappling hook and feather fall in order to avoid the speed cost multiplier if perfectly acceptable. Note that a bridge still counts as a water crossing, unless the hex also has a road. Roads lead directly to bridges, but otherwise the party must follow the river until they find the bridge, which is not ultimately all that different from following the river until they find a ford.

Subtract the speed required to exit the hex from the party’s total speed for the day (or remaining speed, if they have exited a hex already on that day).

Aside: Why Thirty Miles?

30 miles is a very long distance for daily travel. It’s weird that characters can move that quickly by default. Why use 30 miles as the default hex size? There are several reasons. First of all, it means that all questions about how many hexes you can cover if you’re riding [creature] from the Monster Manual are immediately answered. Rather than plugging creature speeds into some complex equation, you just take their fastest relevant speed, divide by 30, and round up.

Secondly, it converts very easily into maps that use the DMG’s recommended size for kingdom or continent scale while still having each hex be big enough to justify the process of walking through it. The DMG recommends kingdom scale be 6 miles per hex, small enough that you’d expect travelers to move multiple hexes in a single day, which is useful for troop movements when being 25% faster means actually covering an extra hex, but bad when you want each individual hex to include a major feature. It means drastically increasing the work required to populate a hex map or else filling up the map with tons of empty hexes that are disappointing to enter. The continent scale is 60 miles per hex, so big that it would certainly take more than one day to move from one hex to another on foot, and requiring enormous speed boosts before you move noticeably faster. A 30 mile scale sits comfortably in between these two. 30 mile hexes are 5 hexes across in kingdom scale and half a hex across on continent scale. This means any hex map that uses either of these scales can easily be retrofitted to use hex crawl scale.

If you aren’t planning on using any official maps as the basis for a hex crawl, or if you don’t mind changing their scale significantly (they’re fictional locations, after all, and changing the distance between Waterdeep and Baldur’s Gate isn’t that different from changing how critical hits work, which is certainly within the GM’s purview), it’s justifiable to instead use thirty kilometer hexes, which is much closer to what you’d expect the average person to cover in a day while also preserving the translation of tactical to strategic speed. The system works identically, although it does mean that you will need more hexes to cover the same physical area, so a 6×6 hex crawl would only cover an area the size of Belgium, and a sizable 10×10 would only be the size of Portugal or Iceland.

Step 4: Roll Constitution Saves

This is an optional step. If the party is out of speed but would really very much like to leave the hex they’re currently in before the end of the day, they can roll a Constitution save for a forced march. For every hour of forced march, they add 0.1 to their speed multiplier for pace (so a slow pace goes from 0.75 to 0.85, a standard from 1 to 1.1, and a fast pace from 1.25 to 1.35), but everyone must make a DC 10 Constitution save, +1 for each hour past the first (so DC 11 for the second save, DC 12 for the third, and so on). A character who fails the save must either take a level of fatigue or else fall behind.

Characters may not take a long rest immediately after exiting a hex but before rolling for random encounters or to spot the hex encounter, so any fatigue taken while traveling will continue to affect them during a random encounter as well as during any hex encounter, although in the latter case the party can usually take a long rest before engaging with the hex encounter (although sometimes the hook for a hex encounter is “something tries to murder you”).

If the characters are marching for an extra nine hours, then there is no longer enough time in the day for them to take a long rest, unless they are elves, in which case they need only four hours of trance for a long rest and it takes thirteen hours of forced marching to prevent them from having one. A party who’ve forced marched this long receives only a short rest whenever they finally go to sleep, unless they sleep in to get a long rest, in which case their speed multiplier for the next day is reduced by 0.1 for each extra hour they must sleep to get a long rest. Fortunately, all of this is fairly rare, since succeeding on nine Constitution saves in a row is really quite difficult.

Step 5: The Party Guide Makes a Navigation Check

Ignore this step if the party is following a road, river, or some other landmark, or if they’re moving directly towards some clearly visible landmark like a mountain or tower on terrain flat enough to keep the landmark in constant or near-constant view. In any of these cases, the party stays on course automatically.

If the party has insufficient speed to actually exit their hex this turn, skip this step. If the party is exiting a hex, the guide must now roll Survival, Investigation, or (at disadvantage) History. The DC for this check varies based on terrain. Coastal, desert, and grasslands terrain make this check at DC10. Arctic, forest, hill, mountain, and blue water terrain make this check at DC 15. Swamp and Underdark terrain make this check at DC 20. If the check succeeds, the party leaves the hex and enters the hex they intend.

If the check fails, the party veers. Roll a d20. On a 1-8, the party has veered left. For example, if they were going north on a map with true columns, they veer left and go northwest instead. If they were going south, a left veer would take them southeast. On a 13-20, the party veers right in the same manner. On a 9-12, by sheer dumb luck the party goes in the direction they intended.

Step 6: Mark Off Supplies And/Or Hunter Rolls Survival

This step is completed only once per day, regardless of how many hexes the party travels through. If the party hunter elects not to hunt in a hex (presumably in order to save his daily hunting for a hex with a lower DC), he cannot reverse that decision after leaving the hex.

The party hunter may make a Survival check at DC 15 in coastal, forest, grassland, hill, and mountain terrain during spring, summer, or fall, DC 20 in any of those terrains during winter (note that some forests, grasslands, etc. etc. are located in a climate that does not have winter, and in these areas the DC will be 15 year-round) or in a swamp or Underdark terrain regardless of season, and DC 25 in desert or tundra terrain. If the hunter succeeds on his check, the party does not have to mark off supplies for the day, however there is not nearly enough time to properly store and preserve hunted or foraged supplies for long term transport, so no amount of success will allow the hunter to increase the party’s food supply.

If the party goes hungry, everyone in the party takes a level of fatigue and does not gain the benefits of a long rest at the end of the day.

Step 7: Enter the New Hex

Ignore this step if the party doesn’t have enough speed to actually enter the new hex today.

There’s nothing to actually do in this step, however all steps from here on in are made based on the hex the party has entered, not the one they were leaving.

Step 8: The Guide Rolls Stealth

If the party is attempting to avoid detection, the guide rolls Stealth and records the result for step 9. Otherwise, ignore this step.

Step 9: Random Encounter

Roll a random encounter on the random encounter table appropriate to the section of hex crawl that the party is now in (and remember that the party has left the hex they were entering and is now in a new hex). Compare the Stealth check (if any) made in step 8 to the passive Perception of the monster (if any) in the encounter. If the Stealth check succeeds, the party has snuck up on the encounter.

Step 10: The Spotter Rolls Perception To Locate Hex Encounter

Every encounter in a hex crawl has a Perception DC required to locate it, ranging from DC 5 for obvious things like castles on a grassland up to DC 30 for incredibly well-hidden features. A single hex can even contain multiple encounters or features in it, each with different Perception DCs (this is not recommended, but mainly just because hex crawls are major undertakings to begin with and it’s probably a bad idea to increase your workload). At this point, the party’s spotter rolls a Perception check, and locate any hex features or encounters that they meet or exceed the DC for. What the party does with that information is, of course, up to them.

If the party has veered off course and become lost, spotting a landmark will usually clue them in as to where they really are. Or maybe they’ll assume there are two exact copies of the same landmark in different locations. How long you let them puzzle over this depends mostly on how funny you think it is watching them try to figure out how and why this village is in two places at once.