Avalon

Avalon is the homeland of Fairies, which is governed by a king, Oberon. Individuals who go here and return, can naturally perceive Fairies. In recent years, fairies have been taking advantage of UFO myths to hide their activities, as the abductions, crop circles, and bright lights they make in the sky are all often attributed to alien encounters.

History
Here, Fairies serve Oberon. There's also a Devil fairy, apparently.

Humans can be taken here aganist their will as seen when Mr. Brennan made a deal with a leprechaun that inadvertently allowed all firstborn human individuals at least from within his in the town, to be abducted and taken to Avalon. Based on comments made by Dean Winchester from the short time he spend in Avalon, all beings here are painfully bright to look at. Dean was later sent back to Earth, due to his reckless behavior but a fairy specifically a redcap, was also sent to punish him for trespassing into their territory. Some humans are also brought by fairies to Avalon for judgment by their Fairy Tribunal. This occurs when humans break the laws of the fairies, such as enslaving a fairy to his or her own will.