It is in Rookgaard, about 83 steps east of the spot the map marks with that name.

And 2 down from the surface once you are there.

• 1 — Rookgaard, as the map itself names it
• 2 — the ground above the treasure

• Something for cyclops, ghoul and rotworm — they live down there.

• 1 — the chest

One chest, one reward.