The Diocese of Tortosa (Latin: Dioecesis Dertosensis) is a Latin church diocese of the Catholic Church covering the south of Catalonia and the north of the Valencian Community.

[1][2][3] The Diocese of Tortosa gives a certain foundation to an ancient historical region that, despite having no political representation, shares common historical, cultural and linguistic ties.

This territory is known as Ilercavonia in academic and scientific circles.

[4] The territory of the historical Diocese of Tortosa was greatly reduced during General Franco's dictatorship, following the Concordat of 1953 between the Francoist regime and the Vatican.

Under the pretext of adapting the dioceses to the civil provincial limits the Consistorial Congregation, bending to the wishes of the dictator,[5] broke up the traditional region of the Diocese of Tortosa: