A Fairy Path or Fairy Road is the route by which the fairies regularly travel between any two locations. These paths can be found in many places and are invisible to anyone without the Second Sight, unless they happen to catch the Fairy folk unaware. Fairy Paths are often said to stretch between known fairy hills or locations but may also be found in more obscure locations.
It is considered very bad luck to build on a fairy path and those who do so always suffer for it one way or another. In the most benign cases the building will suffer from disturbances, often at night, as the fairies pass through the building following their accustomed route. As one source says:
When the house happens to have been built in a fairy track, the doors on the front and back, or the windows if they are in the line of the track, cannot be kept closed at night, for the fairies must march through.
In other instances attempts at building would be destroyed as soon as they were begun by being knocked down and a noted method of testing for a fairy path by those who “could not see them was to put up posts where the building was meant to go and see if they remained standing the next day. In extreme cases the person attempting to build might be killed or suffer extreme misfortune.
The Welsh Tylwyth Teg (“Fair Family”) have fairy paths as the Irish and Scottish fairies do, although their reputation is more dangerous. As one anecdotal source says:
“…the Tylwyth Teg have paths (precisely like those reserved for the Irish good people or for the Breton dead), and that it is death to a mortal while walking in one of these paths to meet the Tylwyth Teg.”
The fairies were known to move their homes at certain times of year, notably on the quarter days, and when they did so they would travel along these fairy paths to get from one hill to another. At any time of year, however, a Fairy Path could be perilous.