The origin of this designation comes from the place where it is sold : the hams were originally shipped abroad from the Port of Bayonne.
In fact, "Jambon de Bayonne" is the product of a whole region : that of the Adour basin.

The geological and weather conditions of the region are particularly well suited to curing ham :
The climate of the Adour basin alternates dry weather under the influence of the southerly wind (known as the "foehn"), and moist conditions from the Atlantic Ocean. This area is situated between the sea and the mountains - from the Atlantic coast to the foothills of the Pyrenees.
The wide variations in relative humidity levels bring alternating periods in which the ham dehydrates, then is humidified.

This particular climate helps the slow maturing of Jambon de Bayonne, thereby ensuring its characteristic tenderness.