Minecraft – Max height of Minecraft mob grinder

I know that this question was asked a long time ago, but just thought I'd give an update and a correction for future people that read this. (please consider that things may also change in future)

Ok, so first of all, you mentioned that a Chunk is 16x16 block around the player. This is incorrect. A chunk is a section of the terrain and is nothing to do with where the player is. The chunk does not move. A chunk is a 16x16x256 (W,D,H). So for the mob spawning. The quote you gave is correct, however, does not note that it is centred around the chunk that the player is standing on. So 7 chunks in every direction from the border of the chunk you are standing in.

And now for your question :) Recently, (not sure when it started) height has become even more important for mob spawning and each chunk is split into segments. This is to reduce the amount the game has to render and does this by going up in 16 block segments starting from 1. So 17, 33, 49, etc. This is called the lc value and can be shown on the debug screen (F3). It is important for mob spawning, why? Because any segments in the chunk above the maximum segment that has anything other than air in do not get checked for spawning conditions. This therefore means that there are many less blocks to check which in theory will make your mob grinder or xp farm more efficient.

There is a fair amount more... however, I think this answers what you wanted. At least I hope it does ;) Best of luck guys.

One way of catching mobs without using water to channel them is a dropper:

X: Cobblestone
S: Sign

SSSSSSSSSSSSSSSSSSS
SXSXSXSXSXSXSXSXSXS
SSSSSSSSSSSSSSSSSSS
SXSXSXSXSXSXSXSXSXS
SSSSSSSSSSSSSSSSSSS
SXSXSXSXSXSXSXSXSXS
SSSSSSSSSSSSSSSSSSS

3 blocks above this cover the whole thing in a layer of cobblestone so that the spawn area is dark. Light the top of the cobblestone to prevent spawning there.

Build your trap a sufficient distance above the ground such that falling mobs will instantly die. Light the ground too. You can build it so that mobs fall into water streams (but still die instantly) so that their items are collected.

This trap takes advantage of the fact mobs treat signs as solid blocks, so will walk straight off a high drop and fall to their deaths. Since it involves no water (pre-murder), it will catch endermen.