The Dreamlands or Dream Realm is a vast, alternate dimension or universe, accessible to earthly humans only through dreams and through which one can enter the Underworld. The waking world is our everyday or "real" universe.
The Dreamlands are for the most part a mirror-image of our waking universe, having, as far as can be determined, the same planets, stars and other cosmic geographical features. However, there are numerous races, civilisations and beings existing in the Dreamlands that do not exist in the waking universe, such as the Zoogs, Gugs, Ghasts, moon-beasts, and others.
- The Plateau of Leng - Home to man-eating spiders and the satyr-like "Men of Leng".
- Celephaïs - a city dreamt into being by its monarch Kuranes, greatest of all recorded dreamers.
- The Forbidden Lands.
- Steps of Deeper Slumber (accessed via the "Cavern of Flame").
- The Enchanted Woods - The place where many enter the Dreamlands.
- Hatheg-Kla - A "high and rocky" mountain in the "stony desert" thirteen days' walk from the village of Hatheg, for which it is named. It is one of the places where the "gods of earth" once dwelt and sometimes return to when they are homesick. (HPL: "The Other Gods")
- Thurai - A White-capped mountains where the gods of earth used to dwell. It is said that at Thurai men mistake the tears of the gods for rain. (HPL: "The Other Gods")
- Lerion - Another mountain formerly inhabited by the gods where the "plaintive dawn-winds" are the in fact their eternal sighs. (HPL: "The Other Gods") Lerion is later described as the source of the river Skai. (HPL: "The Dream-Quest of Unknown Kadath")
- Dylath-Leen - A port recognised as one of the Dreamlands' largest cities.
- Ulthar - A town where no man may kill a cat that lies beyond the river Skai.
- Hatheg and Mir - Neighbouring towns run by Burgesses.
- Hlanith - A coastal jungle city.
- Illarnek - A desert trading capital.
- Land of Mnar - The fabled home of grey stones are etched with strange signs.
- Sarnath - The ruins of a once great civilisation.
- Oriab - An island.
- The Fantastic Realms (HPL: "The White Ship").
- Thalarion - Known as the "City of a Thousand Wonders".
A huge castle atop a mountain and the domain of the "Great Ones", the gods of Earth's Dreamland.
Also known as the Abyss. A subterranean region underneath the Dreamlands inhabited by various monsters.
See also: Events in H. P. Lovecraft's fiction
A hundred and fifty million years ago, during the Permian or Triassic age, the Great Race of Yith on Earth of the waking world exchanged minds with beings from the future for research purposes; including inhabitants of Lomar. (HPL: The Shadow Out of Time)
A million years before the first "true human", Sarkomand - capital city of the Men of Leng - is abandoned and falls into ruin when the moon-beasts enslave the Lengites and take them elsewhere. (HPL: The Dream-Quest of Unknown Kadath)
126,000 years ago, 100,000 before the events of Polaris, a human king of Lomar is among those that exchange minds with one of the Great Race of Yith on pre-human Earth. (HPL: The Shadow Out of Time, Polaris)
c 24,000 BC, when the star Polaris was last positioned as the north star, the arctic city of Lomar was conquered by a people called Inutos; the distant ancestors of modern inhabitants of the arctic. (HPL: The Shadow Out of Time, Polaris)
"Ten thousand years ago", the city of Sarnath stood. It's inhabitants destroyed their pre-human neighbours the Thuum'ha. The city was wealthy for a thousand years but ultimately destroyed by the powers of the Thuum'ha. (HPL: The Doom That Came to Sarnath) Curiously, Iranon claimed to have visited both the site of Sarnath following it's disappearence, and the land of Lomar (which he implied was still standing); suggesting that either Lomar lasted longer than believed or Sarnath existed earlier. (HPL: The Quest of Iranon)
At some point in recent history the inhabitants of Ulthar, impressed by the revenge wrought by some cats upon a couple who liked to trap them, forbade the killing of cats in their town. (HPL: The Cats of Ulthar)