Dimension

Bifrost the Rainbow Bridge to Asgard guarded by Heimdall.

Asgard
Nick Name

The Eternal Realm

Land of Fire and Ice

Land of the Midnight Sun

Indigenous Inhabitants

Elves

Fire Demons

Frost Giants

Norse Gods

Stone Giants

Trolls

Immigrant Inhabitants
Humans
Notable Planets or Celestial Bodies

Alfheim

Realm of the Light Elves

Gundershelm Caverns

Caves of Trolls

Hel

Realm of the Common Dead

Jotunheim

Realm of Giants

Midgard

Earth

Muspelheim

Realm of Fire Demons

Niffleheim

Realm of Dishonored Dead

Nidavellir

Realm of Dwarves

Svartalfheim

Realm of Dark Elves

Valhalla

Realm of the Honored Dead

Vanaheim

Realm of the Vanir "Fair Ones"

Notable Cities

Asgard

City of the Gods

Notable Structures or Monuments
Bifrost: The rainbow bridge that serves as a passage from Asgard to the eight worlds.

Cave of Time: Natural phenomena occurring in a cave on Asgard that allows travel to other periods in time.

Yggdrasil (World Tree): Mystical ash tree which binds seven of the nine realms of Asgard by its roots.  The exceptions are Svartalfheim and Muspelheim.

Notable Residents

Amora

Balder

Fandral

Fenris

Frey

Frigga

Heimdall

Hela

Hermod

Hoder

Hogun

Huginn

Idunn

Jormungand

Kurse

Loki

Muninn

Nidhogg

Odin

Sif

Sigyn

Surtur

Thor

Tyr

Ulik

Vidar

Volla

Volstagg

Ymir

Resources
Various natural and mystical resources, creatures and humanoids native to Asgard.
Special or Unusual Properties
Asgard is on spherical like other planets or planetoids.  It exist as a flat landmass suspended in space, and has about the same top surface size as the continental United States.

Asgard does not rotate nor does it revolve around any known sun.  The principles of day and night, the seasons and gravity appear to be mystical in nature.

Mass on Asgard: earth, wood, stone, steel, water and flesh is denser and heaver than that of Earth and therefore more durable.

Passage between the realms of Asgard is facilitated through numerous inter-dimensional portals.  The only exception of the nine worlds is Midgard (Earth) which is reached from Asgard via Bifrost the rainbow bridge.

Regularly Appearing

Journey into Mystery Vol. 1

Mighty Thor Vol. 1 & 2

First Appearance
Journey into Mystery #85 (Oct. 1962)
Creator
Stan Lee & Jack Kirby
Origin
Asgard is an other-dimensional mystical realm of unknown origin or age that host a wide variety of gods and creatures similar to those of the myths of ancient Scandinavians known as Vikings.
Rainbow Bridge