Is there a limit to how big a multiplayer map could be?

Any information on this?

just the maximum bounds size in the editor (as far as the grids go), so 20x20 km

world origin shifting isn’t supported in multiplayer at the moment (and they have no intention to make it work, if I’m not mistaken)
see the info in the docs:

So the largest multiplayer map we can construct in UE4 is 20x20km?

Out of the box yes, you can always implement origin shifting for multiplayer or instancing using your own network code.

a 100X100X100 map size is Massive for any multiplayer game when you make a landscape, I usually make mine something like 40x40x40 due to 100 being far too huge for my 16player maps.

Then how does Ark: Survival Evolved achieve 48x48 square km?

Seems like this has already been answered by Moss, as per below:

Ark map size is 4x4 km or 36 square km.
UE4 default max size is around ~45x45 km or 2025 square km(As Chosker mentioned - it was 20x20km, but this number has been bumped up in one of updates)

It used to be 5x5, bumped up to 20 in one of the updates. I think Ark is about 7x7, 36 of walkable land mass, but there is also a bit of ocean, it is mostly useless though.

Here is an idea: we actually have 20x20x20 km, and that last 20 which go up are mostly unused. What if we stack landscapes on top of each other, that way we could fit at least 4-5 20x20 km pieces in one map, or even more. Stream them in when necessary and teleport player to a new location. I heard there are some issues with streaming in multiplayer but I am sure there are ways around that. Is this feasible at all? I completely understand that most games don’t need this much land, just interested if this could work.