Asgard, commonly known as the realm of the gods, even referred to as, for those not familiar with heathenry and Norse Mythology, "heaven" to the Germanic peoples. Of course, as heathens we know this not to be true, but it is an interesting prospect.
Way, way back, towards the beginning of time when Odin, Vili and Ve slew the giant Ymir, the three brothers crafted the worlds. The first world in which they crafted (Musphelheim and Nifflhiem were already in existence) was Asgard. They took the skull of Ymir, and set it up into the sky. It was held up by four of the recently created dwarves, named North, South, East, and West.
So Asgard became a home for Odin and those who would later be his kin. It is at this time that Odin, Vili and Ve, become separated and form the two tribes of the gods. Odin, the All-Father forms the Aesir, while Vili and Ve become the fathers of the Vanir.
Asgard the home of the Aesir. As many of you know, the nine worlds are located on three different levels, or tiers. The top tier, is home to Asgard. Thus, Asgard is above us, "the heavens". Most, if not all of the Aesir have large halls located in Asgard in which they live. The most famous of these halls, is of course Valhalla. The hall of the slain, Odin's hall where half of those slain in battle spend their afterlife. Until Ragnarok at least.
Asgard is connected to Midgard by Bifrost, the rainbow bridge. It is by access of this bridge that the gods, and in some rare cases men can travel between the two worlds. It is said that other such bridges connect Asgard to the other worlds.
It is said that the sun always shines in Asgard, the weather (save when Thor is angry) is fair. There are miles upon miles of green fields and forests. It is a utopia. The ruler of Asgard, is of course the All-Father Odin. Everyday Odin and the Aesir hold a council, not only for the governance of Asgard, but for the nine worlds as well.
Hail Asgard and all those who inhabit it!
Nine Worlds of Norse Mythology (ayearandadaywicca.wordpress.com)