It is in Swamp, about 38 steps north-east of the spot the map marks with that name.

And 2 down from the surface once you are there.

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

• Key 5000: a locked door bars the way, and that is the number of the key that opens it.
• Something for giant spider, beholder and slime — they live down there.

The chest is 2 floors under the surface. Going down over it, this is what each floor uses:

1. Ground: down through a ladder.
2. 1 down: down through a ladder.

• 1 — the way in: a ladder, ground
• → — the treasure lies this way

• 2 — a ladder, 1 down
• → — the treasure lies this way

• 1 — the chest
• 2 — the chest

The strongest 14 of 22 kinds whose nests reach this place.

There are 2 chests here under 2 quest numbers, so you can take them all.