Villarreal is a city and municipality in the province of Castellón which is part of the Valencian Community in the east of Spain. The town is locateā¦Villarreal is a city and municipality in the province of Castellón which is part of the Valencian Community in the east of Spain. The town is located at 42 m above sea level, 7 km to the south of the province's capital. Villarreal is separated from Castelló de la Plana by the Millars River. It has 51,367 inhabitants, most of them living in the urban area that covers about 10.7% of its comarca's 55.4 km² surface. Ranked by population, it is the second-largest city in the province, and fifteenth in the Valencian Community.