Foix is a commune, the former capital of the County of Foix. It is the capital of the department of Ariège as it is the seat of the prefecture of that department. Foix is located in the Occitanie region of southwestern France. It is the second least populous French departmental capital, the least populous being Privas. Foix lies south of Toulouse, close to the borders with Spain and Andorra.

The County of Foix was a medieval fief in southern France, and later a province of France, whose territory corresponded roughly the eastern part of the modern département of Ariège.