Forte San Pietro, Coastal fort in Livorno, Italy.

Forte San Pietro is a coastal fort positioned at the edge of the Venice district in Livorno, built with thick stone walls and defensive architecture from the 1600s. The structure features the typical elements of a maritime fortification designed to control access to the harbor.

Construction started in 1682 under Grand Duke Cosimo III de Medici as a defense against attacks from the sea. Over the following centuries, the fort's role changed from military use to storage and other public purposes.

The fort's name honours Saint Peter of Alcantara, and its foundation ceremony was held on 14 July 1682, the birthday of Grand Duke Cosimo III. The governor, Marquis Marco Alessandro del Borro, launched the works that day. After the military role ended, the ramparts housed grain storage pits and later a timber depot, and in the second half of the 19th century the city slaughterhouses were moved inside its perimeter.

The site is easily walkable from central Livorno and situated right at the waterfront with good viewing points. Wear sturdy footwear since the old stone surfaces can be uneven and slippery when wet.

The fort's earthen rampart was hollowed out with pits used to store grain, and after its military role ended the site served as a timber depot. In the second half of the 19th century the city's public slaughterhouses were moved inside its perimeter. Across the Fosso Reale, a gasometer for storing gas was erected in 1845 and dismantled in the 1980s.