Lake Cavazzo or the lake of three boroughs is the largest natural lake of Friuli-Venezia Giulia. It is 9km long, from 400 to 800 meters wide, about 50 meters deep and a surface area of 1.74 sq.km. It is located in the area belonging to the boroughs of Bordano Cavazzo, Carnico and Trasaghis. Of glacial origin it lies at 191 meters above sea level, lower than the river Tagliamento that flows 3km to the east. During very cold winters the surface freezes over.