The Isle of Man

Lying in the middle of the Irish Sea, the Isle of Man is a modest-sized island of some 200 square miles and 80,000 people, with an extremely convoluted political relationship to the UK (it's a Crown Dependency, meaning that it acknowledges the Queen of England as sovereign but has complete autonomy in all but foreign policy and defense). Historically, the Isle of Man was a crossroads of Celtic and Norse cultures, and the Manx have their own language and a folkloric tradition going back millennia. There's a tradition that equates Avalon with the Isle of Man, an origin myth wherein Fionn mac Cumhaill ripped up some land and threw it into the sea (he missed, he was trying to throw it at another giant), and there are faeries found here found nowhere else, like the Fenodyree, the Glashtyn, and the Moddey Dhoo. These days, the Isle of Man relies in roughly equal parts on tourism, manufacturing, and offshore banking to make ends meet (there's pretty much nothing in the way of corporate, inheritance, or capital gains taxes on the island).

The supernatural world tends to treat the Isle of Man as a somewhat more comfortable version of McMurdo Station in Antarctica -- one can do a great deal of interesting research there, but the environment will kill you. At least, if one replaces environment with Fomorians, whose watery domain surrounds the island and whose servants have a long tradition of appearing on the Isle of Man. Nevertheless, there's a small supernatural community in Douglas, the only settlement of note, consisting of perhaps a half-dozen each of fae and mages, with a couple of vampires. There's also a werewolf pack on the island. The current leader of the Manx supernaturals is a Mysterium-aligned wizard by the name of Kumarpal Raam (birth name: Bryan Qualtrough), a Theosophist who is simply too arrogant to let throwbacks like the Fomorians intimidate him.