The Circeo Promontory, in Lazio in the vicinity of the Isola Verde Camping Village in Nettuno, is a small and isolated mountain massif that rises above the Tyrrhenian Sea, together with the promontory of Gaeta, as the extreme southern offshoot of the province of Latina. Among the main peaks, the highest is Monte Circeo, also known as Monte Circello, which can be reached on foot by a medium-difficulty ascent lasting about 4h30″ (a/r) starting from Torre Paola, in Sabaudia.
Surrounded by the Pontine plain, which before reclamation was a vast marshy area, it is plausible that it was once completely surrounded by water. Today it closes, with Torre Paola, the 20 km of beach from Sabaudia to the Marina di Latina, then reopens near the tourist port of San Felice Circeo.