Are elves Celtic or Nordic?

In the vast realm of mythology and folklore, elves often occupy a prominent place, yet their origin and classification remain somewhat mysterious. As a curious observer of such cultural phenomena, I must inquire: Are elves Celtic or Nordic? This question arises due to the rich tapestry of both Celtic and Nordic mythologies, which frequently feature elves in various roles and forms. The Celts, with their deep-rooted history in Western Europe, have long been associated with fairies and other supernatural beings, including elves. Similarly, the Norse mythology of Scandinavia also boasts a diverse array of elves, known as Alfar or Ljósálfar, who occupy a significant place in their pantheon of gods and spirits. So, in this intricate interplay of cultures and mythologies, which cultural tradition can we truly claim as the elves' spiritual home? Is it the mystical woods of Celtic Britain or the icy fjords of the Nordic lands?