In Welsh mythology, the fairy hounds known as the dogs of Annwn are the Cŵn Annwn.
Cŵn Annwn, pronounced roughly “koon AN-noon,” literally means “hounds of Annwn.” They are spectral hunting dogs from Welsh mythology, associated with Annwn, the Otherworld. Medieval Welsh tradition connects them with Arawn, the king of Annwn, while later folklore often places them under Gwyn ap Nudd, another ruler and supernatural hunter.
Their appearance is ominous: they are commonly described as white hounds with red ears, and their howling is treated as a death portent. A striking folkloric detail says that their growls seem loud when the pack is far away but grow quieter as it approaches. They are also linked with the Wild Hunt and, in later interpretations, with escorting souls into the Otherworld.
The hounds appear in the First Branch of the Mabinogi, where Pwyll encounters Arawn’s pack hunting a stag. Christian retellings sometimes called them the Hounds of Hell, but Annwn was traditionally a realm of plenty and eternal youth, not a place of punishment. The Barghest, Cú Sídhe and Cù Sìth are different spectral or fairy-dog traditions.