The island has an area of 274.5 km². It is 24.1 km long and 16.3 km wide.: The tallest mountain on the island (436 m) is near the east coast, in a mountain range named Monte Penoso.: Terras Salgadas is a salty plain in the far north. The northernmost point on the island is Ponta Cais.: 20% of the island area (54.5 km2) is forested and 28% of the island area (76.0 km2) is a protected area. Bays includes Baía do Galeão and Baía da Santana to the north and in the southeast is a lagoon named Lagoa Cimidor. The uninhabited islet Ilhéu Laje Branca lies near its north coast. The island's main town is Porto Inglês, near which its airport, Maio Airport lies.