Arno River. The Arno is a river in the Tuscany region of Italy.
It is the most important river of central Italy after the Tiber. The river originates on Mount Falterona in the Casentino area of the Apennines, and initially takes a southward curve.
The river turns to the west near Arezzo passing through Florence, Empoli and Pisa, flowing into the Tyrrhenian Sea at Marina di Pisa. With a length of 241 kilometres, it is the largest river in the region.
It has many tributaries: Sieve at 60 kilometres long, Bisenzio at 49 kilometres, and the Era, Elsa, Pesa, and Pescia. The drainage basin amounts to more than 8,200 square kilometres and drains the waters of the following subbasins: The Casentino, in the province of Arezzo, formed by the upper course of the river until its confluence with the Maestro della Chiana channel.
The Val di Chiana, a plain drained in the 18th century, which until then had been a marshy area tributary of the Tiber. The upper Valdarno, a long valley bordered on the east by the Pratomagno massif and on the west by the hills around Siena. The Sieve's basin, which flows into the Arno immediately before Florence. The middle Valdarno, with the plain including Florence, Sesto Fiorentino, Prato, and Pistoia. The lower Valdarno, with the valley of important tributaries such as the Pesa, Elsa, and Era and in which, after Pontedera, the Arno flows into the Ligurian Sea. The river h