|Location||At the confluence of the Ringwil and the Narog|
- "...before the proud ones came from over the Sea, Dwarves delved the halls of Nulukkizdîn."
- ― Mîm
Nulukkizdîn was delved by Dwarves before the Elves were exiled from Valinor. Over the years, its population waned, and others were hunted to near-extinction by the Elves, who were unfamiliar with the Petty-dwarves. Nulukkizdîn was eventually abandoned, and repopulated by Elves. Finrod Felagund founded Nargothrond in its stead. After Nargothrond fell to Glaurung, the last Petty-dwarf, Mîm, reclaimed it, but he was slain by Húrin.
Tolkien provided no translations of either Nulukkizdîn or Nulukkhizdīn. The last element is usually believed to be the Khuzdul root for "Dwarf", Kh-Z-D. Whether this is a true Khuzdul word or a Petty-dwarvish dialect is unknown, but circumstantial evidence points to the latter option. The Angerthas Daeron and its specific Dwarven variation Angerthas Moria, do not have a symbol for the letter Î. Other than in Nulukkizdîn, it only appears in Khîm and Mîm, the names of two Petty-dwarves.
 Other versions of the legendarium
In The Silmarillion, the name is spelled Nulukkizdîn; however, Christopher Tolkien has noted that in the original manuscript, his father used the spelling Nulukkhizdīn. It replaced an earlier spelling Nulukkhizidûn.
Tolkien's later notes on the origin of Nargothrond give a different Dwarvish name, Nar(u)kuthûn, derived from a Dwarvish name of the Narog, *Naruka. Tolkien includes the words "of Petty-dwarves" between parentheses behind the mention of its Dwarvish origin. Whether Tolkien ever intended to replace Nulukkhizdīn with Nar(u)kuthûn is unknown.
- ↑ 1.0 1.1 J.R.R. Tolkien, Christopher Tolkien (ed.), The Silmarillion, "Quenta Silmarillion: Of the Ruin of Doriath"
- ↑ 2.0 2.1 Helge Fauskanger, "Khuzdul", published at Ardalambion
- ↑ J.R.R. Tolkien, The Lord of the Rings, Appendix E, "Writing", "The Cirth"
- ↑ J.R.R. Tolkien, Christopher Tolkien (ed.), The War of the Jewels, "The Later Quenta Silmarillion", "Of the Siege of Angband"
- ↑ J.R.R. Tolkien, "Words, Phrases and Passages in Various Tongues in The Lord of the Rings", in Parma Eldalamberon XVII (edited by Christopher Gilson), page 47