Lake Como, with an area of 146 km. is the third Italian lake after Garda and the extension Verbano. It is the fifth deepest basin of Europe (with its 410 meters) after four lakes in Norway. It reaches a length of 46 km (Gera Lario - Como) and a width of 650 meters to 4.3 kilometers. The Bifid fjord is built into the circle of the Pre-Alps of Lombardy, with a characteristic shape of an inverted "Y". This shape is given by the three branches: Colico to the north, Lecco in the south-east, and Como in the south-west, with a total perimeter of 170 km. The maximum length between Como and Gera Lario, is 50 km. The maximum width, between Fiumelatte and Cadenabbia, is 4.4 km. The minimum width between Carena and Torriggia, is 650 m. The maximum depth between Argegno and Nessus, is 410 m. (the greatest of the European lakes), the average height above sea level is 199 m.

The lake is surrounded by mountains of which the highest is Mount Legnone (2609 m) above Colico. The streams have 37 tributaries, among which the most important is the Adda, followed by Mera. The Adda is also the only emissary. It leaves the lake at Lecco and, after forming the lakes Garlate and Olginate, it continues towards the Po .

Lake Como has one of the most beautiful Italian landscapes, praised in 800 by the major poets of Romanticism, by Alessandro Manzoni in Stendhal, George Gordon Byron and Franz Liszt. It is located 199 m s.l.m.

The only island in the lake is the island Comacina, located in the Como branch, opposite the town of Sala Comacina, the German emperor Frederick Barbarossa destroyed the fortress of the islanders in 1169. Since then, the island has been totally uninhabited. The only surviving structures are the seventeenth-century church of San Giovanni (only one remaining of nine attended), the inn with adjoining restaurant (famous for stays of the director Alfred Hitchcock) and small buildings rationalist architect Pietro Lingeri. The ruins of the Basilica of Santa Eufemia Larian are a symbol of history, commemorated annually in the Feast of St. John on the last saturday of June every year. This celebration has its continuity with Varennafest, which is celebrated the following week in Varenna, always on the evening of the first Saturday in July.

North to the Island, there is the village of Lenno with its beautiful Villa Balbianello, which is now run by of the FAI (Fondo per l’Ambiente Italiano / National Trust for Italy). Here many scenes were shot for the films "Piccolo Mondo Antico" and, more recently, Star Wars and James Bond Agent 007 - Casino Royale.