The River Ticino is the largest river in the canton. It drains most of the canton, flowing from the northwest through the Bedretto Valley and the Leventina valley to enter Lake Maggiore near Locarno. Its main tributaries are the Brenno in the Blenio Valley and the Moesa in the Mesolcina Valley in Graubünden. The lands of the canton are shaped by the river, which in its mid portion forms a wide valley, commonly known as the "Riviera".