The beach of Penarronda is located between the councils of Castropol and Tapia de Casariego (Asturias). It is a 600-meter-long beach nestled between two cliffs (La Robaleira and Punta del Corno) and into which the Penarronda or Dola river flows, dividing it in two. The average width is 315 meters and its surroundings are rural. The protected area amounts to 34 hectares, and its wealth comes from the dunes that form a large part of the protected area and are difficult to find in the north, which gives a wealth of vegetation and fauna characteristic of this habitat. It was declared a natural monument in 2002.