The Tiber (Italian Tevere, Latin Tiberis) is the third-longest river in Italy, rising in the Apennine mountains of Tuscany and flowing 406 km (252 miles) through Umbria and Latium to the Tyrrhenian Sea. It drains a basin estimated at 18,000 km² (6845 square miles). The river achieved lasting fame as the main watercourse of the city of Rome, founded on its eastern banks.

The river rises at Mount Fumaiolo in central Italy and flows in a generally southerly direction past Perugia and Rome to meet the sea at Ostia. Popularly called flavus ("the blond"), in reference to the yellowish colour of its water, the Tiber is heavily charged with sediment. Sedimentary deposition from the river has caused the coastline to advance at each mouth by about 3 km (2 miles) since Roman times, leaving the ancient port of Ostia Antica 6 km (4 miles) inland.

The city of Rome was founded on the banks of the Tiber about 25 km (16 miles) from the sea at Ostia. The island (Isola Teverina) in the center of Rome, between Trastevere and the ancient center, was the site of an important ancient ford and was later bridged. Legend says Rome's founders, the twin brothers Romulus and Remus, were abandoned on its waters, where they were rescued by a she-wolf.

The river marked the boundary between the lands of the Etruscans to the west, the Sabines to the east and the Latins to the south. Benito Mussolini, born in Romagna, adjusted the boundary between Tuscany and Emilia-Romagna, so that the springs of the Tiber would lie in Romagna. By the limpid spring was erected an antique Roman column, inscribed QUI NASCE IL TEVERE SACRO AI DESTINI DI ROMA ("Here is born the Tiber, sacred to the destinies of Rome").

It was critically important to Roman trade and commerce, as ships could reach as far as 100 km (62 miles) upriver; there is evidence that it was used to ship grain from the Val Teverina as long ago as the 5th century BC. It was later used to ship stone, timber and foodstuffs to the growing city.

During the Punic Wars of the 3rd century BC, the harbour at Ostia became a key naval base. It later became Rome's most important port, where wheat, olive oil, and wine were imported from Rome's colonies around the Mediterranean. Wharves were also built along the riverside in Rome itself, lining the riverbanks around the Campus Martius area. The Romans connected the river with a sewer system (the Cloaca Maxima) and with an underground network of tunnels and other channels, to bring its water into the middle of the city.


The heavy sedimentation of the river made it difficult to maintain Ostia, prompting the emperors Claudius and Trajan to establish a new port on the Fiumicino in the 1st century AD. They built a new road, the via Portuensis, to connect Rome with Fiumicino, leaving the city by Porta Portese ('the port gate'). Both ports were eventually abandoned due to silting.

Several popes attempted to improve navigation on the Tiber in the 17th and 18th century, with extensive dredging continuing into the 19th century. Trade was boosted for a while but by the 20th century silting had resulted in the river only being navigable as far as Rome itself.

The Tiber was once notorious for its floods - the Campus Martius is a flood plain and would regularly flood to a depth of several metres. The river is now confined between high stone embankments which were begun in 1876.