Region lying south of Lake Geneva
It belonged to the County of Savoy from its early days in the 11th century. At that time the region was known as New Chablais, the original Chablais being the lands either side of the Rhône as it flowed to Lake Geneva.
The great abbey of St Maurice stood in this original Chablais, much of which was lost by Savoy by the late 12th century, so that the name became confined to New Chablais.
Chablais was temporarily lost to the Swiss in the 16th century, when the west was held by the city of Bern, 1536-67 and the east was held by Valais, 1536-69. It was temporarily part of France, 1796-1814 (in the Department of the Léman), and permanently French from 1860 (in the Department of the Haute-Savoie).