Midgard

The only one of the Nine Worlds that’s primarily located in the visible world;

The name “Midgard” (“Middle Enclosure”) has a double meaning. The first meaning of the word refers to civilization’s position “in the middle of” an otherwise wild world, which is reflected on the cosmological plane by Midgard’s being surrounded by the uninhabited wilderness of Jotunheim, the world of the often-hostile giants. This is akin to the way in which the continents are surrounded by the ocean, which is, in the ancient Germanic perspective, also teeming with giants. The serpent Jormungand lives in the sea and encircles the terrestrial Midgard and the wilderness at its borders, and Aegir and Ran dwell in the same watery depths and claim the lives of unfortunate seafarers. You might call this part of the word’s meaning “horizontal.” The second and “vertical” sense of the word’s meaning refers to Midgard’s position below Asgard, the world of the Aesir gods and goddesses, and above the underworld. This vertical axis is represented by the world-tree Yggdrasil, which holds Asgard in its upper branches, Midgard at the base of its trunk, and the underworld amongst its roots.

When the gods gave the world its initial shape, they slew the giant Ymir 

and created the various part of the world from his body parts.

In order to protect Midgard and humanity from the giants,

they built a fence around Midgard out of Ymir’s eyebrows. 

Asgard

The home and fortress of the Aesir, one of the two tribes of gods (the other being the Vanir, who have their home in Vanaheim). Asgard is located in the sky^[1] (albeit spiritually rather than physically, of course) and is connected to Midgard, the world of humanity, by the rainbow bridge Bifrost.

The -gard element in Asgard’s name is a reference to the ancient Germanic concept of the distinction between the innangard and utangard. That which is innangard (“inside the fence”) is orderly, law-abiding, and civilized, while that which is utangard (“beyond the fence”) is chaotic, anarchic, and wild.

This applies both to the geographical plane and the human psyche; thoughts and actions can be innangard or utangard just as readily as spatial locations. Asgard is the ultimate model of the innangard, while Jotunheim, the “Homeland of the Giants,” is the epitome of the utangard.

Vanaheim

One of the Nine Worlds that are situated around the world-tree Yggdrasil.

As the name implies, it’s the home of the Vanir tribe of deities, who tend to be somewhat more associated with fertility and what we today would call “nature” than the other tribe of Norse deities, the Aesir, who have their home in Asgard.

Jotunheim - Utgard (pronounced “OOT-guard;” Old Norse Útgarðr, “Beyond the Fence”)

World of the Giants.

At the center of this cosmology are Asgard, “The Enclosure of the Aesir Deities,” and its human counterpart, Midgard, “The Middle Enclosure.” Asgard is the divine model of the innangard. Midgard, the visible world and especially human civilization, is patterned upon the divine model. The “Middle” element in its name largely refers to its being surrounded by – in the middle of – Jotunheim.

In the Eddas, the dwelling-places of the giants are described as deep, dark forests, mountain peaks where winter never eases its grip, and similarly inhospitable and grim landscapes, and this certainly seems to be how the heathen Norse and other Germanic peoples symbolically visualized the invisible Jotunheim itself.

Nilfheim

World of Fog”) is one of the Nine Worlds of Norse mythology and the homeland of primordial darkness, cold, mist, and ice. As such, it’s the opposite cosmological principle of Muspelheim, the world of fire and heat.

Muspelheim

The World of Múspell is the home of the fire giants.

Muspelheim features in both the creation of the world and its downfall. In the creation narrative given by Snorri, fire from Muspelheim and ice from Niflheim meet in the middle of Ginnungagap and forge the giant Ymir, the first being from whose corpse the world was eventually shaped. 

Alfheim

The Homeland of the Elves.

Alfheim is never described in the sources that form the basis of our current knowledge

of heathen Germanic religion, but is rather merely mentioned in passing in a few places.

The Vanir god Freyr is said to be the ruler of Alfheim

Nidavellir/Svartalfheim

 the home of the dwarves/dark elves

Mastersmiths and craftsmen who live beneath the ground.

Accordingly, Nidavellir or Svartalfheim was probably thought of as a labyrinthine, subterranean complex of mines and forges.

There stood in the north
In Nidavellir
The golden hall
Of Sindri’s family.

Unfortunately, then, we know only the vaguest outlines of what the Vikings thought the homeland of the dwarves was like.

Hel (underworld)

The underworld where many of the dead dwell.

It’s presided over by a fearsome goddess whose name is also Hel.

Occasionally, it’s also referred to as “Helheim

The fact that Hel and Hell are both realms of the dead located beneath the ground, the two concepts have nothing in common.

While the Old Norse sources are far from clear on exactly how one ended up in one of the Norse afterlife realms rather than another (there were several), what is clear is that where one goes after death isn’t any kind of reward for moral behavior or pious belief, or punishment for immoral behavior or impious belief.

The Old Norse sources describe in uncharacteristic detail the course that one has to travel in order to reach Hel.

It even has a name that comes up repeatedly in Old Norse literature: Helvegr, “The Road/Way to Hel.”