Chasm City is a 2001 science fiction novel by British writer Alastair Reynolds, set in the Revelation Space universe.

It deals with themes of identity, memory, and immortality, and many of its scenes are concerned primarily with describing the unusual societal and physical structure of the titular city, a major nexus of Reynolds's universe.

Tanner arrives to find that Yellowstone, the most advanced civilization in human history, has descended into squalor; an alien nanotech virus known as the Melding Plague has wreaked havoc throughout the system.

The Glitter Band, a sparkling diorama of ten thousand orbital habitats, has been reduced to a "Rust Belt" of a few hundred survivors, mostly primitive and pre-nanotech antiques.

From the depths of the gas plume at the heart of Chasm City, to the aristocratic canopy spanning what remains of the skyscrapers, Mirabel begins to unravel the mystery of the Melding Plague.