The seabedsbetween Capo Circeo and Terracina constitute the largest SPA in the Lazio Region, covering an area of 5,385 hectares. This site is located within the municipalities of San Felice Circeo and Terracina and it falls within the Mediterranean biogeographic region. The Posidonia oceanica meadows is the most noteworthy feature of the site: it is an aquatic plant of significant ecological importance as it provides habitat for numerous marine species.