Mende was the capital of a large and ancient diocese in the southern parts of the Massif Central that coincided with the county of Gévaudan. Situated on the river Lot, about ten miles to the west of its springs and ten miles to the northwest of Mont Lozère – at well over 5,500 feet the highest elevation between the Rhône and the Atlantic coast – it dominated the easternmost extension of a long and tortuous valley that slowly descends in a western direction until it opens onto the plains of Aquitaine where, a few miles to the west of Agen, the Lot merges into the Garonne. Roughly speaking, the county has the shape of an oval with a radius varying from about twenty to thirty miles that is cut in half by the Lot and has its centre in Mende itself. The northern half is composed of two mountainous plateaus joined in the middle by a ridge that is formed by the Monts d'Aubrac in the northwest and the Montagnes de la Margeride in the north and northeast.