Les Assions is located some 35 km south-west of Aubenas and 5 km north-east of Les Vans. Access to the commune is by the D104A road from Lablachère in the north passing through the heart of the commune just east of the village and continuing south to join the D295 near Vompdes. The D452 branches off the D104A in the commune and goes east by a circuitous route to the Village de Vacances Francaises de Casteljau. The D104 from Lablachère to Saint-Paul-le-Jeune forms the eastern border of the commune. Access to the village is by a country road (Le Village) branching north from the D104A in the south of the commune. Apart from the village there are the hamlets of Le Bosc in the west, Le Bourel and La Ribeyrie to the north-east and Champetier-Haut in the north. The commune east of the Salindres river is mostly wasteland and forest while the west side is mostly forest with farmland and residential areas.[3]
The Chassezac river forms the southern border of the commune as it flows east to join the Ardeche at Saint-Alban-Auriolles. The Riviere de Salindres flows south through the commune to join the Chassezac and several other tributaries rise in the commune and flow into the Chassezac.[3]
The vegetation includes predominantly oak trees, olive trees and chestnut trees.
