ancient Garumna
River, southwestern France.
The most important river of southwestern France, it is 357 mi (575 km) long. Formed by two glacial headstreams in the central Spanish Pyrenees , it flows north through mountain passes and descends to flow east across France. It continues to Toulouse and then to Bordeaux , where it is 1,800 ft (550 m) across. Flowing by the wine-growing Entre-deux-Mers peninsula, it unites with the Dordogne River 16 mi (26 km) north of Bordeaux to form the vast Gironde estuary .