It lies at the end of the south-eastern branch of Lake Como (the branch named Lake of Lecco). The Prealps rise to the north and east, cut through by the Valsassina of which Lecco marks the southern end. The lake narrows to form the river Adda, so bridges were built to improve road communications with Como and Milan. There are three bridges crossing the river Adda in Lecco: the Azzone Visconti Bridge (1336-1338), the Kennedy Bridge (1956) and the Alessandro Manzoni Bridge (1985). Its economy used to be based on industry (iron manufacturers), but now it is mainly tertiary.