[RPG] Is weapon reach measured from the edge of the mount’s space or the rider’s


So, if a medium or small creature, like a PC, controls 25 square feet, (a 5×5' area) and a large creature, like a horse controls 100 square feet, (a 10×10' area) and tactical combat takes place on a 5' grid, (no, I'm not budging on that, yes I know it's optional) and melee weapons either have a reach of 5' or 10'…

During mounted combat, does a rider's attack extend from the edge of his mount's controlled area, or from the edge of the area he personally controls on his mount?

Or rather, put another way,

During mounted combat, is a rider assumed to control the same space as his mount, regardless of size differences?

Best Answer

Reach is measured from the rider


Nothing in the rules says that mounting another creature changes your size. So, according to the most basic reading of the rules, your size simply does not change. There are no secret rules and this is both the simplest and most RAW answer.

So that would make the answer to your second question a definitive "no". While mounted your character maintains its original size and thus the space they control also stays the same regardless of mounted state or mount size.

To your first question, it would seem the answer would be that you weapon's reach, attack origin, and anything else related to your character's position would also not change.

However, this does not rule out the possibility of the character moving squares on the mount itself to make attacks (instead of staying centered on the mount).Jeremy Crawford also said that when using a grid and miniatures you can "fit" the rider in any square occupied by the mount,and that you can move around on your mount using your movement (here).

RAI agrees

Jeremy Crawford also agrees in a Tweet (now just unofficial guidance):

Being mounted doesn't change your character's size.