The Agoo–Damortis Protected Landscape and Seascape is located on the eastern side of Lingayen Gulf in southern La Union, Philippines. It was established in 2000 to protect 10,648.94 hectares (26,314.1 acres) of coastal area, including mangrove swamps, seagrass beds and stretches of fine black sand beaches. It was first gazetted as a national park in 1965 and was known as the Agoo–Damortis National Seashore Park. It covers approximately 30 kilometres (19 mi) of coastline of the Lingayen Gulf shared between the municipalities of Agoo, Santo Tomas and Rosario.