Foix (fwä) [key], town (1990 pop. 10,466), capital of Ariège dept., S France, on the Ariège River at the foot of the Pyrenees. It is an administrative and tourist center with some small industry. It grew around an oratory founded by Charlemagne and became the capital of the countship of Foix. The most famous of the many powerful Foix counts was Gaston III. Foix was united with the crownland in 1607. Of interest are an imposing château (12th and 14th cent.; restored), which now houses a museum of prehistoric, Gallo-Roman, and medieval art; and the ancient St. Volusieu Church (reconstructed in the 14th and 17th cent.).