France–Spain border
The France–Spain border (French: Frontière entre l'Espagne et la France; Spanish: Frontera entre España y Francia) was formally defined in 1659. It separates the two countries from Hendaye and Irun in the west, running through the Pyrenees to Cerbère and Portbou on the Mediterranean Sea. It runs roughly along the drainage divide defined by the Pyrenees, though with several exceptions.