Pigeon Key is a historic district located on the small island of Pigeon Key in the lower Florida Keys. The island is named "Cayo Paloma" on many old Spanish charts. It is located off the old Seven Mile Bridge, at approximately mile marker 45, west of Knight's Key, (city of Marathon in the middle Florida Keys) and just east of Moser Channel, which is the deepest section of the 7 mile span.
Said to be named for large flocks of White-crowned pigeons (Columba leucocephala Linnaeus) which once roosted there. During the building of Henry Flagler's Overseas Railroad Key West Extension, a major construction depot was located there, the jumping off point for construction of the Seven Mile Bridge. A number of buildings from the Flagler era remain on the island. They are now part of the Pigeon Key Historic District.