Surrounded by common Bompas, Mercus-Garrabet, Surbiton and Tarascon-sur-Ariege, Arignac is located 516 meters above sea level, in the heart of the Ariege valley, 14 km south of Foix, Ariege prefecture.
Ariege River and Creek Courbière are the main rivers that cross the common Arignac. The trout fishing is popular.
Arignac is a municipality in the Regional Natural Park of the Ariège Pyrenees.