Before this capture the Nive had deposited pebbles from the Mindel glaciation of medium to large sizes that slowed erosion of the hills causing the bottleneck at Bayonne.After the deposit of the lowest alluvial terrace (10 to 15 metres (33–49 feet) high at Grand Bayonne), the course of the Adour became fixed in its lower reaches.The inhabitants of the commune are known as Bayonnais or Bayonnaises.Bayonne is located in the south-west of France on the western border between Basque Country and Gascony.In the 17th century the city was fortified by Vauban.In 1814 Bayonne and its surroundings were the scene of fighting between the Napoleonic troops and the Spanish-Anglo-Portuguese coalition led by the Duke of Wellington: the city then underwent its final siege.At that time the first bridge was built over the Adour.
The occupation of the hill that dominates this narrowing of the valley developed through a gradual spread across the lowlands by building embankments and the aggradation from flood soil.
The loss of trade with the English and the silting up of the river as well as the movement of the city towards the north weakened it.
The district of Saint-Esprit developed anyway thanks to the arrival of a Jewish population fleeing the Spanish Inquisition.
Bayonne occupies a territory characterized by a flat relief to the west and to the north towards the Landes forest, tending to slightly raise towards the south and east.
The city has developed at the confluence of the Adour and Nive 6 kilometres (3.7 miles) from the ocean.
The meeting point of the two rivers coincides with a narrowing of the Adour valley.