The Dordogne begins at Puy de Sancy (1m), the highest point in the Massif Central, in the Monts Dore range. It merges with the Garonne to form the Gironde estuary, after crossing the department of Dordogne and part of that of Gironde.
Between the bastide of Sainte-Foy-la-Grande and that of Libourne, its course is made of meanders at the foot of the hills from where the vineyards come to meet it.
The entire Dordogne basin has been classified Biosphere Reserve by UNESCO July 11, 2012. On this occasion, the Dordogne basin joined the World Network of Biosphere Reserves which, in 2020, brings together 701 exceptional sites across the five continents.
The Isle has its source in the Massif Central, department of Haute-Vienne, south of the hamlet of Rongeras in Janailhac, at the foot of the granite hills of the canton of Nexon.
It then meanders through the department of Dordogne, waters the town of Périgueux and enters the department of Gironde at Saint-Antoine-sur-l'Isle, after having covered nearly 180 kilometres. Up to La Fourchée (Coutras), the river flows peacefully in long meanders in the middle of the plain. It flows into the Dordogne at the foot of the bastide of Libourne, this is where it adopts its maximum width of about 50 to 60 meters.
The Dronne has its source at an altitude of 480 meters, in the Périgord Limousin regional natural park. It crosses Coutras and, a kilometer and a half further to the south-west, flows into the Isle.