The Merse is an Italian river, a right tributary of the

Ombrone The Ombrone (Latin: ''Umbro'') is a river situated in the provinces of Grosseto and Siena, central Italy. The Ombrone's source is at San Gusmè, near Castelnuovo Berardenga, on the south-eastern side of the Monti del Chianti. After a twistin ...

. It runs through

Tuscany Tuscany ( ; ) is a Regions of Italy, region in central Italy with an area of about and a population of 3,660,834 inhabitants as of 2025. The capital city is Florence. Tuscany is known for its landscapes, history, artistic legacy, and its in ...

for a distance of about 70 km and is the river of the Val di Merse. Its sources are near Poggio Croce di Prata and Poggio di Montieri in the range of hills known as the Colline Metallifere. From here it takes a north-easterly direction for the first half of its course before turning sharply to the south-east. At Pontiella it receives from the right the waters of the Farma, a torrent born at Torniella, again in the Colline Metallifere). After a few kilometres the Merse enters the

at Pian di Rocca which lies half-way between the spa of Bagni di Petriolo to the west and Castiglione del Bosco to the east. The river has recently suffered from sulphurous pollutants deriving from the old and neglected mine-workings in the upper part of its course. Fish are far less plentiful than in the past, which may be put down to the exploitation of its waters for irrigation during the summer months; nevertheless there are many

cyprinids Cyprinidae is a family of freshwater fish commonly called the carp or minnow family, including the carps, the true minnows, and their relatives the barbs and barbels, among others. Cyprinidae is the largest and most diverse fish family, and t ...

, and pike are also found. The white mill which gives its name to the Mulino Bianco biscuit manufacturers is located on the upper course of the river: it was constructed in the early 13th century by monks from the nearby abbey of Serena.

External links

L'inquinamento del Merse

Rivers of the Province of Grosseto Rivers of the Province of Siena Rivers of Italy {{Italy-river-stub