Club Deportivo Castellon, S.A.D. is a professional Spanish football team based in Castellon de la Plana, in the Valencian Community. Founded in 20 July 1922, it currently plays in the Segunda Division, holding home games at Nou Estadi Castalia, which has a capacity of 15,500 seats.
Football first appeared in the town in 1911, and after a period of time under the consecutive denominations "Deportivo", "Castalia", "Gimnastico", "Cultural" and "Cervantes", Club Deportivo Castellon was founded on 22 July 1922.
The club featured periodically in the top flight, finishing fifth in 1972–73 and adding a Cup final appearance with a team featuring Vicente del Bosque, who later moved to Real Madrid, serving the club as both a player and coach.
On 29 August 1991, in an extraordinary assembly, the conversion of the club to S.A.D. was approved. The first team had just relegated into division two, and would drop another level to the third three years later, in a spell which would last more than one decade.