I am trying to decide on a location as the setting for a fairy-lore related MG fantasy novel. As I understand it, different places have differing oral traditions, so in turn many of the fairy tales we know today are associated with certain places or regions – for example (and not limited to fairies), we think of elves as Celtic, trolls as Scandinavian, and vampires as Transylvanian.
Thinking of the UK, Ireland and Brittany and their fairies, are different regions associated with different types of fairies? Or are there regions that are more intimately related to fairies than others? Is there, so to speak, a "map of Celtic fairy lore"?
I know this information can be deduced from the sources given in folkloric collections, but it would be a Ph.D.'s worth of work to extract that, so I admit I shy away from doing it. But maybe someone has done it, or it is something a native of the UK or France would know?
(I'm not asking about individual fairy tales that mention a specific place, such as the Eildon Hills in Thomas of Erceldoune, but about areas where certain types of stories are more prevalent.)