Old Moria

In the Elder Days, Durin the Deathless found his way to the lake of Kheled-zâram in the valley of Azanulbizar (or the Mirrormere in the Dimrill Dale, as it was known to Men). Seeing the stars of the Crown of Durin shining in the waters of the lake, he chose that place to build his mansions, and set about carving into the Mountains of Moria at the head of the valley.

The entry that he made would become the Great Gates of Khazad-dûm, and behind those Gates the Dwarves made a network of immense interconnected chambers. Defences were also put in place at this time, including the famously narrow Bridge of Khazad-dûm. These first chambers and passageways behind the East-gate formed the beginnings of Khazad-dûm, and in later days they were known as Old Moria. From these early underground mansions, the Dwarves would continue to work, eventually extending their realm beneath the entire range of the Misty Mountains so that its West-gate opened onto the lands beyond.

The term 'Old Moria' comes from the end of the Third Age, when the Dwarves had long been forced out of their great mansions by Durin's Bane. The deserted halls were soon filled by hordes of Orcs, and the name Moria - meaning 'Black Chasm' - alludes to this fall. At the city's ancient height, it was known by its Dwarvish name of Khazad-dûm, and so presumably the Dwarves of these earlier times used some more suitable name than 'Old Moria' for the ancient heart of their realm.