Udûn

The land of Mordor was surrounded on the north and west by long mountain ranges, with Ered Lithui guarding the land from the north and Ephel Dúath running along its western border. In the northwest, these two ranges came together, and where they met they formed a wide, flat-bottomed valley some thirty miles from end to end. The valley was surrounded by mountain walls, but narrow passes at either end provided a way into Mordor through its fence of mountains.

When Sauron established himself in Mordor in about the year II 1000 and began the construction of his Dark Tower, he also set about fortifying the valley that led into his new land. From about this time, the valley acquired the name Udûn. This name came from Sauron's own history, being the Sindarin form of Utumno, the immense ancient stronghold of the first Dark Lord, Melkor, who had been Sauron's master.¹

Mordor was protected to the north and west by its mountain ranges, and so the valley of Udûn between the ranges was the weakest part of the land's defences. It was therefore heavily fortified, with its narrow entrances to the northwest and southeast both being solidly defended. The outer, northwestern pass, Cirith Gorgor, was guarded by the immense Black Gate of iron named the Morannon, flanked in later years by the two Towers of the Teeth. To the south, the pass leading onto the Plateau of Gorgoroth was named Carach Angren, or the Isenmouthe. Lying far behind the Morannon, this pass was less strongly defended than its northern counterpart. Nonetheless, it too was flanked by forts and guarded by rows of spiked iron posts. As well as these defences, Carach Angren was defended by a high rampart and a deep ditch that could only be crossed by a single bridge.

Between these two narrow passes, the valley walls were filled with Orc-holds and armouries ready to stand against any invader of the Dark Land. A single straight road led across the valley floor from the Morannon in the north, running for some thirty miles to reach Carach Angren in the south. After leaving Udûn through the guarded southern pass, it split into three branches leading west, south and east across the Plateau of Gorgoroth.

At the time of the War of the Ring, the forces of Mordor were mobilised and a great part of those forces were assembled in Udûn, ready to march out northward through the Morannon. On 25 March III 3019, a small force from Gondor and Rohan, led by the Captains of the West, approached the Black Gate to challenge Sauron. After a brief parley, the Morannon was opened and the armies set out from Udûn and into battle.

As that battle was underway, the earth suddenly shook as Mount Doom convulsed, revealing that the march of the Captains of the West had been a feint. With his forces thus distracted, the One Ring had been cast into the Fire, and with its destruction Sauron's power failed. This brought about the fall of the Dark Tower, and wrought devastation on the land of Mordor. The last we hear of the valley of Udûn, it lay in ruin and chaos.