The Hounds of Annwn (Cŵn Annwn) are mythical, supernatural dogs from Welsh folklore, representing the otherworldly pack of the Welsh Otherworld, Annwn, often led by kings like Arawn or Gwyn ap Nudd as part of the Wild Hunt, appearing as ghostly white hounds with red ears and eyes, heralding death or escorting souls, their baying mistaken for geese in autumn nights, a classic symbol of Celtic death omens and the boundary between worlds.

Key Characteristics & Roles:
- Appearance: Large, spectral hounds, typically described as white as snow with red ears and glowing red eyes, though variations mention black or liver-coloured hounds.
- Leader: Associated with Arawn, King of Annwn, or later with Gwyn ap Nudd, the underworld figure who leads the Wild Hunt.
- The Hunt: They participate in the Wild Hunt, a spectral chase across the sky, often at Samhain or during winter.
- Omens: Their baying, sometimes mistaken for geese, is a powerful death omen; hearing them and being able to count them (often thirteen) signifies doom, but fewer might mean escape.
- Connection to Otherworld: They are messengers and guardians of Annwn, the mystical realm of the dead, but also a place of paradise, linking life and death.
Cultural Significance:
- Pre-Christian Roots: They represent ancient beliefs about the afterlife, predating Christian demonization, where they were once pure fairy hounds.
- Psychopomps: They guide lost souls to the Otherworld.
- Symbolism: They embody the transition of seasons, the mystery of death, and the thin veil between the human world and the spirit realm.