Yonne (river)

The Yonne is a river in the northern half of France. It flows mainly through the western part of the Bourgogne-Franche-Comté region, giving its name to the Yonne department and to several "communes". It is the main left tributary of the Seine river.
The river was named during the Roman Empire as "Icauna", a Latin word that likely came from the Celtic name for the river.
Geography.
The Yonne river has a length of and a drainage basin with an area of .
Its average yearly discharge (volume of water which passes through a section of the river per unit of time) is 91.70 cubic metres per second at Courlon-sur-Yonne.
Course.
The source of the Yonne is on the "Prénely" mountain on the southern end of the "Morvan" hills in the Glux-en-Glenne "commune", Nièvre department, at an altitude of about .
The Yonne flows, in general, from the southeast to the northwest and passes through the 115 "communes", most of them in the Bourgogne-Franche-Comté region; the main "communes" are:
Finally, it flows, as a left tributary, into the Seine river in the town of Montereau-Fault-Yonne, at of altitude.
Main tributaries.
The main tributaries of the Yonne are: