The game spawns new areas with the monsters / other clans etc dynamically, as in, while you dig, this isn't a predefined world.

If when you dig, you place orders to only dig two tiles at a time in any given direction, then you won't trigger the creation of these areas. This is helpful when building a new settlement: by doing this you can make sure it's as large as you want without getting blocked by stuff.

Wow, i didn't know that. I'm in crystal world right now and this would been so helpful at the start for me! Thanks!

be aware that each "world" has a limit for max expansion to the sides and the depth
the side borders arnt a problem but if u hit the border downwards you could screw up the storyline!

ofc it is save to use this "dig only 2 tiles" to create your "city" in a compact way without annoying rng caves :)

just dont use it to often if u already expanded ur current "world" far into the ground, and dont use it all the time to dig down
(yeah...yeah u need to do this quite heavily to screw it up but the option is there)

There is a mod that turn off the cave generation all together, so this problem doesn't exist anymore. Neither do those extra resources though