Casillas de Camineros is the name in Spanish given to structures built every 6 kilometers during the latter part of the 19th century alongside the major roads built in Puerto Rico and provided as residences to the "camineros", specially-trained government workers charged with providing maintenance to the surface of approximately six kilometers of a major road. Abandoned in the latter part of the 20th century, the structures have faced different fates. Many of them have deteriorated or been demolished. Others have been put to other uses.