Located on the Sargaso continent, Gollum’s dwelling lies at the farthest of Sargaso’s southeastern reaches; submitted into the pitch black of a swamp infested, boulder confinement that’s drenched with ample fish and other sea creatures to feed upon. There are only a few narrow, arduous tunnels that lead to his dank cave.
Gollum’s dwelling is a vast, widely spread establishment of jagged rocks and caved-in tunnels; it’s a labyrinth to his particular household. Dwarves are the most common of races that bare habitation around his cave, besides the dangerous monsters that lurk in Sargaso’s bordering seas. Gollum’s obsession with a ring (and other assorted gems, artifacts, etc.) leaves him to run rapid in his own tunnels, discovering new passageways in the process; in which he uses trickery (by leaving nourishment, light, signs, etc.) to fool his oncoming adventures/disrupting trespassers.
Temperature wise the cave, as the underground is suited, is a delightfully cool breeze of winds that whistle into its mouth (where the ships of Jacmus are able to acknowledge Gollum’s dwelling). Once passed the shrill chill of the cool inside the dingy burrow, it becomes slightly warmer for idle swamps to acquire tepidity and attract prey (fish, etc.) into its netting meshes.
If you need a looks-see of his cave, bring up the Sargaso continent, and look to its southeastern tip. The deformity that looks like something had taken a bite from it; go into that at an angle, and when the dark starts to surround the (blue) sea’s waters, that’s where a more precise location of Gollum’s dwelling lies.