Castiliscar is a municipality located in the province of Zaragoza, in the Aragon region of Spain. It is one of the many small settlements that make up this autonomous community in northeastern Spain, within the comarca of Cinco Villas.
According to the 2004 census carried out by the Instituto Nacional de Estadística (INE), the municipality had a population of 395 inhabitants. This figure reflects the modest size typical of many rural municipalities in the Zaragoza province.