 The Diocese of Tortona maintains a list of parishes on its own website.In 2014 there was one priest for every 1,674 Catholics.Cardinal Carlo Alberto Guidobono Calvachini (1683-1774), the pro-Datary of Pope Clement XIV, a native of Tortona and a former student of the Jesuit College of Tortona, carried out the reconstruction of the parish church of S. Giacomo in Tortona.