Fanzara is a municipality in the comarca of Alto Mijares, in the province of Castellón, part of the Valencia region of Spain. It is a small inland settlement situated in the mountainous interior of the province, within the Alto Mijares district, an area of narrow valleys and hill country in the north of the Valencian Community.
As a municipality, Fanzara forms the basic unit of local administration in Spain, with its own local government. Its setting in the Alto Mijares places it among the rural villages of Castellón's inland comarcas, which are characterised by low population densities and a landscape shaped by the Mijares river system and its surrounding sierra.
Beyond its administrative status and location, Fanzara is best known for its association with the Alto Mijares comarca and the wider province of Castellón. The municipality's territory lies at the transition between the coastal plains of the Valencia region and the more rugged terrain of the interior, a position typical of the villages in this part of Spain.