Aizac is located some 30 km east of Langogne and 40 km west of Livron-sur-Drome close to the Monts d'Ardeche Regional Nature Park. Access to the commune is difficult with only three circuitous roads entering the commune. From Vals-les-Bains in the south the D578 goes north then left to the D243 which eventually comes close to the western border of the commune where there is a right turn to the D443 which enters the commune and joins the D254 at the village. The D254 road enters the commune from Labastide-sur-Besorgues in the north-west and continues through the commune exiting on the eastern side intersecting with the D578 which goes north and south. Other than small mountain roads no other roads enter the commune. The village is very small with only a few houses and there are a few other houses scattered through the commune.[2]
There are many streams throughout the commune such as the Ruiseau des Fuels, the Bise, the Coupe, the Rousses, the Ribeyres, and the Sandron most of which flow to the Ardeche river in the south.[2]
