Castellón de la Plana, officially Castelló de la Plana, or simply Castellón/Castelló, is the capital city of the province of Castellón, in the Valencian Community. It is located in the east of the Iberian Peninsula, on the Costa del Azahar by the Mediterranean Sea. The mountain range known as Desert de les Palmes rises inland north of the town.
According to the 2018 census, Castellón has a population of 174,264 inhabitants, ranking as the fourth most populated city in the Valencian Community. The Prime Meridian, or Greenwich Meridian, intersects the 40th parallel at Castellón de la Plana and is commemorated with a monolith in Meridian Park located at the exact point where this occurs.