Lake Como is about 29 miles (47 km) long and up to 2.5 miles (4 km) wide, with an area of 56 square miles (146 square km) and a maximum depth of 1,358 feet (414 m). It receives the Adda River, which enters it near Colico and issues from it at Lecco, and also the waters of numerous other rivers and mountain streams, including the Mera. It is subject to frequent floods and is swept by two winds, the tivano from the north in the morning and the breva from the south in the afternoon. Its northern arm once probably extended as far as Chiavenna, enclosing the area now covered by Mezzola Lake. Como is associated with the classical writings of Virgil, the two Plinys, and Claudian.

A luxuriant lakeshore vegetation includes vines and fig, pomegranate, olive, chestnut, and oleander trees. There is fishing for trout, eel, and agoni, a type of herring, but pollution has much reduced the fish population. The lake is famous for the natural beauty of its setting and for the handsome villas on its shores. Among the many noted lakeside resorts are Como, Lecco, Bellagio, Tremezzo, Menaggio, and Varenna. Several towns are connected by steamer services.