Fontanone di Ponte Sisto, Baroque fountain in Trastevere, Rome, Italy.

The Fontanone di Ponte Sisto is a Baroque fountain in Rome featuring three water outlets with lion-shaped spouts and ornamental dragon carvings. A raised upper basin and decorative stonework define its structure and make it a focal point on Piazza Trilussa.

Paolo V had the fountain built between 1608 and 1613 to carry Acqua Paola water across the Ponte Sisto to the Ospizio dei Cento Preti; Giovanni Vasanzio and Giovanni Fontana directed the work. The hospice was demolished around 1880 for the Tiber embankments and the fountain dismantled. In 1898 Angelo Vescovali rebuilt it at the opposite end of the bridge, recovering only about half the original stones.

The dragons carved at the base of the columns are the heraldic animals of the Borghese family, the patrons of Pope Paul V who commissioned the fountain. The name "Cento Preti" comes from the hospice for retired priests in the building behind it. The upper basin is now dry and the jets reduced to two thin streams.

The fountain stands at the top of a staircase in Piazza Trilussa, at the south end of Ponte Sisto, on the Trastevere bank. From the opposite bank of the Tiber it can be seen in line with the Fontanone dell'Acqua Paola on the Janiculum above. Water flow is now much reduced: the upper basin and the lion mouths are dry, and the dragons give only two weak streams.

During the Napoleonic occupation, the papal emblem was removed from this fountain as a symbol of political takeover. Many of its original stones were later repurposed as building material elsewhere in the city, leaving traces of Rome's turbulent past.