The Venetian Lagoon is an enclosed bay of the Adriatic Sea, in northern Italy, in which the city of Venice is situated. Its name in the Italian and Venetian languages, Laguna Veneta—cognate of Latin lacus, "lake"—has provided the English name for an enclosed, shallow embayment of salt water, a lagoon.

Venice is a city in northeastern Italy and the capital of the Veneto region. It is built on a group of 126 islands that are separated by expanses of open water and by canals; portions of the city are linked by 472 bridges. The islands are in the shallow Venetian Lagoon, an enclosed bay lying between the mouths of the Po and the Piave rivers. In 2020, around 258,685 people resided in greater Venice or the Comune di Venezia, of whom around 51,000 live in the historical island city of Venice and the rest on the mainland (terraferma). Together with the cities of Padua and Treviso, Venice is included in the Padua-Treviso-Venice Metropolitan Area (PATREVE), which is considered a statistical metropolitan area, with a total population of 2.6 million.