The Clitunno, in Antiquity the Clitumnus, is a river in Umbria, Italy. The name is of uncertain origin, but it was also borne by the river god. The Clitunno rises at 42°49.5′N 12°46′E / 42.8250°N 12.767°E from a spring within a dozen metres of the ancient Via Flaminia near the town of Campello sul Clitunno between Spoleto and Trevi: the spring was celebrated as a great beauty spot by the Romans but also by Byron and Giosuè Carducci; in the 19th century it was planted with willows, and jealously monitored for pollution, it is open today as a paying tourist attraction.
The Clitunno then flows 60 kilometres (37 mi) through the east Umbrian plain, past the Temple of Clitumnus and the towns of Pissignano, Cannaiola, Trevi and Bevagna to join the Topino River, a tributary of the Tiber, near Cannara. Though its current is usually sluggish, it is subject, like many other rivers in the east Umbrian plain, to sudden flooding: it was only tamed completely in the 19th century, and is largely banked by levees.