Sauron had used Mount Doom to forge his One Ring, and at the foot of Mount Doom he built his stronghold Barad-dûr. Sauron chose to settle in Mordor one thousand years after the First Age ended, and it remained his kingdom for the entirety of the Second and Third Ages of Middle-earth. What is known is that the east was a heavily defended area containing a border of forts facing towards Sauron's allies in Rhun.

The east of Mordor is not mentioned often in descriptions of Mordor. Mordor as seen on a map of Middle-earth, marked with red. Directly east lies Rhûn, the Eastlands, and to the west lies Khand. The narrow land of Ithilien with the city of Osigiliath lies to the west of Mordor. The land was somewhat fertile due to the ashes from Mount Doom, allowing dry-land farming. Núrn, in the southern part of Mordor, was more fertile and sufficiently moist to house the inland sea of Núrnen. Mordor was protected from attacks on all fronts because of its unscalable mountains, while the arid lands of Gorgoroth and Núrn caused great attrition to armies that did manage to break through, preventing them from staying there for a prolonged period of time. The plateau of Gorgoroth lies to the south-west of Barad-dûr, and so does Mount Doom to the east lies the plains of Lithlad. Sauron's Dark Tower, the fortress of Barad-dûr, was located at the foothill of the Ash Mountains.

The only viable large entryway into Mordor lies in the north-west corner of Mordor: the deep valley of Udûn protected by the Black Gate of Mordor. The Ash Mountains lie in the north and the Mountains of Shadow in the west and south. Mordor is protected by three mountain ranges on all sides.

Middle earth shadow of mordor mods