Screwpile lighthouses, also known as screwpile lighthouses or screwpile structures, are a type of lighthouse structure which was popular during the 19th and early 20th centuries. They were built by driving metal piles into the seabed and then constructing a superstructure on top. Screwpile lighthouses are often constructed in areas where the seabed is soft or sandy, making it difficult to construct traditional masonry or stone lighthouses.