Monte Argentario is a comune (municipality) and a peninsula belonging to the Province of Grosseto in the Italian region Tuscany, located about 150 km south of Florence and about 35 km south of Grosseto.
The peninsula is connected with the mainland by three spits of land which form two lagoons, the Laguna di Ponente on the west side and the Laguna di Levante on the east side of the middle dam.
The two main villages on Monte Argentario are Porto Santo Stefano, facing north, and Porto Ercole facing south.
The panoramic road Strada panoramica starts in Porto Santo Stefano allowing splendid views of the coast and the Tuscan Archipelago.
Monte Argentario borders the comune of Orbetello, which is located on the middle dam between the two lagoons. Monte Argentario is a promontory stretching towards the Tyrrhenian Sea in correspondence of the two southernmost islands of the Tuscan Archipelago, Giglio and Giannutri.
The promontory was an island in the past, but the sea currents and the Albegna river joined it with the mainland through two so-called tomboli (stretches of land), The Tombolo of Giannella and the Tombolo of the Feniglia. The highest peak of Monte Argentario is the Punta Telegrafo (635 m).
The landscape and the coast are mainly rocky; numerous harbors, usually with rock beaches, are present.
The municipal seat is in the northern settlement, Porto Santo Stefano. The other main settlement in the township is Porto Ercole.