Lago di Mergozzo (En. Lake Mergozzo) is a small sub-alpine lake in northern Italy just to the west of Lago Maggiore and north of Lago d'Orta, at the mouth of the Val d’Ossola in the province of Verbano Cusio Ossola, Piedmont. (790 m) rises from the south-west shore of the lake; the limestone rocks of which it is composed are heavily quarried. On the opposite side of the lake the mountains form the beginning of the chain which divides the Val d’Ossola from the and its National Park.