Vall de Almonacid is a municipality in the comarca of Alto Palancia, in the province of Castellón, within the Valencia region of Spain. It is known in Valencian as La Vall d'Almonesir, although the local language spoken in the area is Spanish rather than Valencian.
The town is situated in the Alto Palancia district, an inland comarca of Castellón that lies in the northern part of the Valencia region. As a municipality, Vall de Almonacid forms part of the local administrative structure of the province, with its own municipal government.
Its dual naming reflects the linguistic situation of the area: the Valencian form La Vall d'Almonesir is used officially alongside the Spanish name Vall de Almonacid, but Spanish is the language spoken locally. The municipality is one of several small towns that make up the Alto Palancia comarca.