Gorgoroth

The northern half of Mordor was a high plateau enclosed by the Ephel Dúath on the west, the Ered Lithui on the north, and the fall of the land towards Nurn on the south. This was Gorgoroth, the plain of dread: a desert of ash, cinders and broken rock, pitted with craters and heaped with slag, without water or grass. Over it hung the smoke of Mount Doom, which stood alone near its middle, and at its eastern edge, on a spur of the northern mountains, rose Barad-dûr. Roads built by Sauron crossed it from the Isenmouthe and from the Morgul Pass to the Dark Tower, and along them were camps of Orcs and the ordered tents of the Men of the East and South mustered for his wars. Between the plateau's western edge and the main wall of the Ephel Dúath ran a lower inner ridge, the Morgai, and in the trough between the two a few thorns and briers grew and a little foul water ran.

Gorgoroth was empty in the days of Gondor's watch and filled again with Sauron's forces after his return in the Third Age. In March 3019 the plateau was thick with armies; from the Morgai on March 15 Frodo and Sam looked out over it and saw the camps stretching for miles, and knew that they could not cross unseen while the host was there. They went north along the Morgai instead and were driven by an Orc-column through the Isenmouthe on March 18 and 19. When the armies had marched to the Black Gate, the hobbits struck out across the plain on foot, discarding their Orc-gear and finally most of their belongings, rationed to the last mouthfuls of water. Six days of crawling and walking brought them to the foot of Mount Doom on March 24; Sam carried Frodo the last part of the way. After the Ring was destroyed the plateau shook, the earth split and fire ran across it, and the armies gathered on it perished or fled.

Gorgoroth occupied north-western Mordor from the Morgai to the spur of Barad-dûr, and from the Isenmouthe in the north-west to the slopes falling towards Nurn in the south. Mount Doom stood some forty miles south-east of the Isenmouthe.