The majestic Porta San Marco was built between 1835 and 1840 on a project by Alessandro Manetti and Carlo Reishammer (who was also the author of the church of San Leopoldo in Follonica). Along with the Porta San Leopoldo, this gate was one of the first examples in Tuscany of combining elements in cast iron with traditional materials, such as ashlared stone. In addition to a massive stone structure, the gate indeed presents a series of elements in cast iron designed to be produced in series and industrially realised. The prefabricated elements assembled to form the architecture of the internal arching were created by the grand-ducal Foundry of Follonica.

The Porta San Marco was also the monumental entrance to Livorno for travellers arriving by train. The Leopolda Station, which constituted the end of the new Florence-Pisa-Livorno railway, was indeed built right in front of it around 1840. The railway was later extended to the harbour station. With the construction of the new railway station in 1911, the Porta San Marco station gradually lost its importance, to the point of becoming a simple freight yard. Of the original building, deprived of its iron and glass gallery around 1940, only the characteristic U-shape and traces of a pair of rails remain. Already partially restructured as a residence, the Station area today is part of a project of urban rehabilitation.