Fidra lies a short distance off the East Lothian shore, between Gullane and North Berwick. The island is split into two at high tide. The southern part has an old volcanic plug known as the Castle. On the main part of the island there is a path leading from the small harbour up to the lighthouse and there are still the remains of an old trackway where supplies were winched up to the lighthouse. To the north of this path there is a natural arch through the cliffs. On the south side is the ruined wall of St Nicholas Chapel.