The town hall of Lagosanto stands at zero metres above sea level, and that makes it the least elevated comune in Italy; the lowest point in Italy, on the other hand, is nineteen kilometres from here, at Contane, in the territory of Jolanda di Savoia. The comune was born in 1013, when the powerful abbey of Pomposa granted a territory to the Lagosanto community. Until the reclamation of the lower Ferrarese the village was surrounded on three sides by the valli, Pega, Ponti and Trebba, and in piazza Vittorio Veneto stands the monument to the fiocinino, the man with the fish-spear: fishing in the valli di Comacchio, poaching included, is the tradition the village has chosen as its symbol.
Part of those valleys had belonged to Lagosanto, but the rogito Giletti, drawn up between the Napoleonic French delegation and Comacchio, sold them all to the comune of Comacchio, which became their sole legitimate owner. After Napoleon's fall, in 1814, the community of Lagosanto went to law, accusing Comacchio of misappropriation and of having been favoured by the French. The case lasted more than a hundred years and closed in 1927 with an award in Comacchio's favour: Lagosanto stayed within the narrow borders it still has, and the rivalry between the two villages has stayed as well. Since then the place has lived on farming; the Antica Fiera d'Agosto reached its 449th edition in 2023, and in 2001 the Ospedale del Delta was opened.