Yuth is a ruined undersea city which features in the fictional Cthulhu Mythos.
Located around thirty miles north of the Bimini Islands beyond the chain's oceanic shelf and deep beneath water, Yuth is a gargantuan city composed of thin cones hundreds of feet in height engraved with enigmatic runes, and squat squarish buildings which have for the most part been knocked flat by seismic upheaval. Despite the ruined nature of the cones, many of them retain their sharp tips, and so remain a forest of hazards to those attempting to descend to the city.
Yuth is an entirely alien city to humans, with much of it's geometry said to be painful to look at. What is known is about its ground level is that it reaches farther than any human has explored, and has at least one - now broken - causeway which stretches for further than the eye can see. One end of this causeway terminates in a vast temple, home of the Great Old One Tsathoggua, who was believed to have lived there.
- In John Glasby's short story The Old One, several humans attempted to explore Yuth and one, Professor Dorman, was snatched from there by Tsathoggua.
- Although Tsathoggua is stated to have taken residence in Yuth, this goes against most other sources which claim that he sleeps in the subterranean realm of N'kai.