The Nera is a 116-kilometre (72 mi) long river that flows almost entirely in Umbria in central Italy. It is the largest tributary to the Tiber (Tevere), its sources are in the Sibillini Mountains (Monti Sibillini) east of  Foligno. It flows southward past Terni and Narni. It joins the Tiber near Otre. Its largest tributaries are the Velino and the Corno.