at Heorot: eight horses with gold-plaited bridles, an embroidered banner, a new helmet, chain-mail, and a new sword. Even the other warriors receive lavish gifts for their part in defeating Grendel. So, Heorot presents as a place that generally exhibits a positiveatmosphere.

In contrast to Heorot, Grendel's lair is miserable, loathsome, and dark. Grendel is said to dwell in the moor-fens. Fens are wetlands, created by decaying matter in wet terrain. So, a fen is definitely a dismal place to live, quite unlike Heorot Hall. Grendel is so accustomed to living in the cheerless moors that he finds the merry atmosphere of Heorot almost unbearable. In the poem, we are told that the moor-fens are "mist-covered." It is always dark there; it is uninhabitable by humans and not readily accessible. Grendel and his mother live where wolves roam, where the air is unhealthy, and where the weather is always unpleasant.

They guard the wolf-coverts,
Lands inaccessible, wind-beaten nesses,
Fearfullest fen-deeps, where a flood from the mountains
’Neath mists of the nesses netherward rattles,
The stream under earth: not far is it henceward
Measured by mile-lengths that the mere-water standeth,
Which forests hang over, with frost-whiting covered,
A firm-rooted forest, the floods overshadow.

This is a great question. At first glace, there seems to be nothing in common between Heorot and Grendel's lair. Heorot is bright, covered in hammered gold and designed for celebration. It stands high in the land, "towering magestic" (according to Raffell's translation), and shines with the glory of the Danes. Grendel's lair, on the other hand, is underwater, dark, and foreboding. Grendel, described as a descendent of Cain, moves with evil intent, and his lair reeks of malice.

However, upon consideration, there are some similiarities between the two. Heorot is the hall where great victories are celebrated and remembered. It is filled with the plunder from those victories, artfully worked, and made to last of iron covered with gold. Grendel's lair is also made to last, a stone cave hidden under the water, inaccessible to man. Grendel's lair is also filled with the spoils of his conquests, as evidenced by the sword of the giants with which Beowulf slays Grendel's mother.

Both places are tributes to pride: one of honor, one of malice. Both contain reminders of great victories, and both reflect the souls of the builders.

Heorot Hall and Grendel's Lair are so opposite of one another that a contrast between the two would be as obvious as light and dark. In fact, Grendel lives in such a way that he is "harrowed" by the merriment and song that come from Heorot.

The mead hall of Heorot is described as a place of great celebration, where King Hrothgar hosts great feasts and presents his loyal warriors with lavish gifts. In fact, the hall is said to be large enough for Hrothgar to have presented Beowulf with a gift of eight horses.

While Grendel lives at least close enough to Heorot to hear the song coming from the hall, his own abode could not be more opposite. Grendel lives in dank marshlands where the weather is always miserable. Grendel and his mother are implied to be descended from Cain. For this reason, it is their curse to always live in harsh and barely habitable regions such as swamps and fens.

Herot is the Anglo Saxon word for "heart".  It is the center of all the activity of the city, and the lifeblood by which the city operates.  It is full of ceremony and celebration.  It is also the place where the King's throne is set--a throne that has been "blessed by God" and so therefore is off-limits to Grendel. 

Grendel's home, on the other hand, is dark, dank, miserable, and void of happiness or love.  There couldn't be a more obvious contrast.

In the text, Heorot is described as helearna maest, "the best of halls." It was deliberately crafted to be the epitome of what a mead-hall should be, with the work of many people from different nations contributing to this "folcstede fraetwan," or "hall of folk." Heorot is the center of the community and from its inception has been a symbol of togetherness. It is "high and horn-gabled," but it is not its physical beauty which awakens Grendel's displeasure. Rather, it is the "noises of revelry" from within the hall which make Grendel, sé þe in þýstrum bád ("he who dwelled in darkness"), feel inclined to attack. The defining feature of Heorot, then, is that it is a place where people come together to enjoy themselves, a place where boasts are made and rings exchanged, the symbols of pacts and relationships in Anglo-Saxon communities. Grendel is excluded from this, dwelling alone in darkness.

Grendel is an "infamous stalker in the marshes," "fen ond faesten"—the desolate stronghold of the fens is his home. The idea of "the fens" recurs in Old English poetry as representative of the hinterlands outside of the warm glow of acceptable society. As an outcast living in these hinterlands, Grendel is "in darkness" in contrast to the light of Heorot, and he is alone by contrast to those who enjoy togetherness in Heorot.

In describing Grendel's home, the poet actually says "men ne cunnon / hwyder helrunan / hwyrftum scríþað," which means "nobody knows where hellish enigmas like this make their homes." However, the poet is certainly sure that wherever Grendel's home is, it is not like Heorot. After Beowulf has wounded him, Grendel flees "to seek his joyless abode."

The mead hall is a place of comfort for the warriors. It is a place where loyalty is rewarded by the king and reputations are gained. The author describes it as a place of light, warmth, and good cheer, where the community meets to eat, drink, sing and enjoy one another. Contrasting this is the description of Grendel's home. Here is a dark, murky place where the water itself burns and the animals fear to go. The author goes so far as to say animals would rather die than drink from the lake. There is no community, only the lonely, outcast souls of Grendel and his mother. It is a place of doom and isolation.

This question, seemingly simple on the surface, has importance in the dissection of the story’s structure.  Beowulf can be read as a saga of communality—the blending of societies, the friendships forged between nations, etc.  Heorot is the place where Mankind find refuge in comradeship, in collaboration, in mutual respect, in societal membership.  Grendel lives with his mother in a cave under stagnant water, not only far from other creatures, but isolated as a species also.  The anonymous author did not provide many details of this solitary creature and his mother, because Grendel is simply a manifestation (or rather, an animated embodiment) of non-human forces that social creatures fear because they bring chaos to an ordered world.  In this respect, Beowulf is simply a “fairy-tale”, the genre that fictionalizes and dramatizes human fears—Hansel and Gretel is a story of childhood desertion, for example).  While it is usually seen as a war saga, it functions as well as a “scary story” that early Western culture told itself.  A study could be done of all “dwellings” or “habitats” in fairy tales—the witch’s house, Rapunzel’s tower, the Seven dwarfs’ cottage (and the mine where they work), Grandma’s house, the Three Little Pigs’ straw house, etc.—and Beowulf could be added—to reveal how domestic environs act as paysages moralise (moral landscapes).  Heorot is a place of comeradeship.  Grendel's cave is a place of isolation.