Commentators have noted that Mordor was influenced by Tolkien's own experiences in the industrial Black Country of the English Midlands, and by his time fighting in the trenches of the Western Front in the First World War.

Others have observed that Tolkien depicts Mordor as specifically evil, and as a vision of industrial environmental degradation, contrasted with either the homey Shire or the beautiful elvish forest of Lothlórien.

[1] To the west lay the narrow land of Ithilien, a province of Gondor;[T 2] to the northwest, the Dead Marshes and Dagorlad, the Battle Plain; to the north, Wilderland; to the northeast and east, Rhûn; to the southeast, Khand; and to the south, Harad.

[T 7][T 8] Inside the Ephel Dúath ran a lower parallel ridge, the Morgai, separated by a narrow valley, a "dying land not yet dead" with "low scrubby trees", "coarse grey grass-tussocks", "withered mosses", "great writhing, tangled brambles", and thickets of briars with long, stabbing thorns.

The core of Sauron's realm was in the northwest: the arid plateau of Gorgoroth, with the active volcano Mount Doom located in the middle.

[T 6][T 4] Núrn, the southern part of Mordor, was less arid and more fertile; Sauron's slaves farmed this region to support his armies,[T 11] and streams fed the salt Sea of Núrnen.

[T 4] Mount Doom, Orodruin, or Amon Amarth ("Mountain of Fate") is more than an ordinary volcano; it responds to Sauron's commands and his presence, lapsing into dormancy when he is away from Mordor, and becoming active again when he returns.

[T 10] Tolkien stated in his "Guide to the Names in The Lord of the Rings", intended to assist translators, that the phrase "Crack of Doom" derives from William Shakespeare's play Macbeth, Act 4 scene 1.

He further states that "Doom" originally meant "judgement", and by its sound and its use in the word "doomsday" carries the "senses of death, finality, and fate".

"[T 20] In The Return of the King, Sam Gamgee witnessed the destruction of Barad-dûr: "... towers and battlements, tall as hills, founded upon a mighty mountain-throne above immeasurable pits; great courts and dungeons, eyeless prisons sheer as cliffs, and gaping gates of steel and adamant..."[T 20] Barad-dûr, along with the One Ring, Mordor, and Sauron himself, were destroyed on 25 March, a traditional Anglo-Saxon date for the crucifixion; the quest to destroy the One Ring began in Rivendell on 25 December, the date of Christmas.

This was based on a First Age world-map drawn by Tolkien in the Ambarkanta, where the Inland Sea of Helcar occupied a large area of Middle-earth between the Ered Luin and Orocarni, its western end being close to the head of the Great Gulf (later the Mouths of Anduin).

Gondor built fortresses at the entrances to Mordor to prevent his return, maintaining the "Watchful Peace" for over a thousand years.

At the time of Bilbo Baggins's quest in The Hobbit, Sauron returned into Mordor from Dol Guldur, feigning defeat, but readying for war.

It was carried into Mordor by two Hobbits, Frodo Baggins and Sam Gamgee;[T 22] they approached via the Dead Marshes, and entered by the pass of Cirith Ungol.

[12] Against this, the philologist Helge Fauskanger notes that Tolkien had been using both the elements of the name, "mor" and "dor" (as in Gondor, Eriador) for decades before assembling them into "Mordor".

[T 26] The medievalists Stuart D. Lee and Elizabeth Solopova compare Tolkien's account of Mordor and the neighbouring landscapes to the monster Grendel's wilderness in Beowulf.

[13] In particular, they compare Frodo and Sam's crossing of the Dead Marshes and what Gollum called its "tricksy lights", with Beowulf's "fire on the water"; and their traversal of the parched Morgai, full of rocks and vicious thorns, with Grendel's dangerous moors.

[15] The critic Chris Baratta notes the contrasting environments of the well-tended leafy Shire, the home of the hobbits, and "the industrial wastelands of Isengard and Mordor.

"[16] Baratta comments that Tolkien clearly intended the reader to "identify with some of the problems of environmental destruction, rampant industrial invasion, and the corrupting and damaging effects these have on mankind.

"[16] The New York Times related the grim land of Mordor to Tolkien's personal experience in the trenches of the Western Front in the First World War.

[18] Jane Ciabattari, writing on the BBC culture website, calls the hobbits' struggle to take the ring to Mordor "a cracked mirror reflection of the young soldiers caught in the blasted landscape and slaughter of trench warfare on the Western Front.

It is contrasted, writes Guanio-Uluru, with the beauty of Lothlorien, and marked by negative adjectives like "harsh, twisted, bitter, struggling, low, coarse, withered, tangled, stabbing, sullen, shrivelled, grating, rattling, sad".

The attack in both cases is from the East: over the Balkan hills or the Ephel Duath; across the plains of Hungary or Ithilien; over the river Danube or Anduin; supported by "wild Tartar horsemen" or "eastern cavalry"; the siege of the walls by "Turkish sappers" or Mordor's Orcs; relief by a battle further downstream, whether by Charles, Duke of Lorraine of Imre Thokoly's army, or by Aragorn over the Corsairs of Umbar; and the breaking of the siege by an army from the north, whether Polish forces or the Riders of Rohan.

In the first film, Sean Bean, playing Boromir, the warrior from Gondor, declares to the Council of Elrond that "one does not simply walk into Mordor".

[23] In the final film, Frodo and Sam struggle across the shattered volcanic plain of Gorgoroth to Mount Doom,[21] dressed as orcs, under the red glare of the volcano and the watchful Eye of Sauron from an exaggeratedly Gothic Barad-dûr,[24] while the Army of the West gathers for the final battle in front of the Black Gate and witnesses the cataclysmic destruction of everything Sauron had built when the Ring is destroyed.

[21] For Jackson's film trilogy, Richard Taylor and his design team built an 18 ft (5 m) high miniature ("big-ature") of Barad-dûr.

[25] Jackson's The Lord of the Rings: The Return of the King movie (2003) showed Barad-dûr as clearly visible from the Black Gate of Mordor, which is not the case in the book.

In Womack's view the 2019 biopic Tolkien explicitly connects Mordor to trench warfare: "riders become bloody knights; smoke billows and turns into the form of dark kings.

[34] In the city of Warsaw, Poland, an area in the south-western district of Mokotów, in the neighbourhoods of Służewiec and Ksawerów, is commonly known as Mordor.