Raso (7 km2) is the most interesting islet in the archipelago of Cape Verde. It is situated between Santa Luzia and São Nicolau, and is close to Branco, another islet. It has an altitude of 164 m, is 3,600 m long and 2,770 m wide. The landscape is distinguished by a broad plain on the south side, which contrasts with the rugged coast and central and northern flank.
In 1990, the islets of Raso, Santa Luzia and Branco were declared a nature reserve. Today it is forbidden to disembark unless in possession of a permit issued by the government of Cape Verde. However, the only surveillance is carried out by a non-governmental organization, Biosfera I, which has led intensive on-site campaigns to prevent the traditional annual killing of Cory’s shearwaters. Visitors usually depart from São Nicolau, the closest island, but also from São Vicente and Santo Antão. In recent decades, apart from fishermen, growing numbers of ornithologists and birdwatchers visit the island in hired fishing boats from Tarrafal (São Nicolau), the nearest place of habitation to Raso. The main purpose of these trips is to spot the native Raso lark and seabirds that breed on the islet.