Lovecraft said that the story was based on a dream, which was in turn inspired by the last line of Lord Dunsany's story "The Probable Adventure of the Three Literary Men", quoted in the story itself: "the unreverberate blackness of the abyss".

Another identified source is the 9th Edition of the Encyclopædia Britannica, whose description of "Irem, the City of Pillars" he copied into his commonplace book: "which yet, after the annihilation of its tenants, remains entire, so Arabs say, invisible to ordinary eyes, but occasionally, and at rare intervals, revealed to some heaven-favoured traveller."

Critic William Fulwiler argues that Edgar Rice Burroughs' At the Earth's Core was one of Lovecraft's primary inspirations for "The Nameless City", citing "the reptile race, the tunnel to the interior of the earth, and the 'hidden world of eternal day'" as elements common to both tales.
More generally, Fulwiler suggests, the theme of "alien races more powerful and more intelligent than man", which recurs frequently in Lovecraft's writings, may derive from Burroughs' Pellucidar stories.
However, both writers drew on an already existing and vast literature of "lost city" stories and novels.
Lovecraft said that the story was based on a dream, which was in turn inspired by the last line of Lord Dunsany's story "The Probable Adventure of the Three Literary Men", quoted in the story itself: "the unreverberate blackness of the abyss".
Another identified source is the 9th Edition of the Encyclopædia Britannica, whose description of "Irem, the City of Pillars" he copied into his commonplace book: "which yet, after the annihilation of its tenants, remains entire, so Arabs say, invisible to ordinary eyes, but occasionally, and at rare intervals, revealed to some heaven-favoured traveller."
Critic William Fulwiler argues that Edgar Rice Burroughs' At the Earth's Core was one of Lovecraft's primary inspirations for "The Nameless City", citing "the reptile race, the tunnel to the interior of the earth, and the 'hidden world of eternal day'" as elements common to both tales. More generally, Fulwiler suggests, the theme of "alien races more powerful and more intelligent than man", which recurs frequently in Lovecraft's writings, may derive from Burroughs' Pellucidar stories. However, both writers drew on an already existing and vast literature of "lost city" stories and novels.
The Nameless City