The Lazzeretto fort was a coastal defensive structure located in Porto Santo Stefano, the capital of Monte Argentario, at the western end of the Porto Vecchio.
The complex was built by the French in 1805, during the Napoleonic period, with the dual functions of a coastal defensive structure and a place of quarantine for those who contracted serious infectious diseases (at that time there were some cases of yellow fever in the area).
The part of the complex used for defensive functions was equipped with a battery capable of hitting any enemy vessels that approached it; however, in 1808 the fort was captured by British soldiers who unexpectedly arrived in a series of boats.
In the mid-nineteenth century, the defensive complex was strengthened and, later, the quarantine rooms were abandoned and transformed into local health offices. Passing under the jurisdiction of the Kingdom of Italy, the structure continued in its defensive functions, partially integrating the Pozzarello fort which was built further east.
The structure was partially destroyed during the bombings of the Second World War; in its place was built the building that houses the headquarters of the maritime compartment of Porto Santo Stefano.
The lost fort of the Lazzeretto appeared as a building with a rectangular plan which was divided into two levels. Along the main facade it was equipped with two rectangular entrance doors, interspersed with quadrangular windows, which also opened on the upper level. The upper part culminated in a four-slope roof.
