The name Benàco has Latin origins, although, as far as the present name, Lake Garda, is concerned it is not possible to establish with accuracy where it came from, it is presumed that it comes from the town of the same name, Garda, as during the Medieval age this was the centre for most of the commerce for the entire coastal area of the lake. Lake Garda has glacial origins, in actual fact, there was an enormous glacier along the trough of the lake, the traces of this can be found in the deposits discovered on the Tremosine uplands and in the Barbarano valley. In the southern area the morainic hills are arranged in circles that lower as they move inwards. This is the largest Italian lake, it is 51 km long with a maximum width of 17.5 km and the average depth is 65 m above sea level and its maximum depth is off the shores of Brenzone with 350 m. The northern area of Lake Garda is enclosed by two mountain ranges, to the east is that of Monte Baldo and to the west is that formed by Tremalzo – Coblone – Pizzocolo. The two towns of Torbole and Riva del Garda are part of the province of Trento, the eastern part is in the province of Verona and the western part in the province of Brescia. The main tributary is the river Sarca which originates in the Adamello area and flows into Lake Garda between Torbole and Riva del Garda; the Mincio, however, has a single outlet at Peschiera del Garda. Lake Garda has several islands, the largest is that of Garda, and amongst the smallest Olivo and Trimelone are worth mentioning, the latter has the ruins of a military fort.