Roman Catholic Diocese of San Marino-Montefeltro Tags: Clerical Administrative Region, Diocese.The Italian Catholic Diocese of San Marino-Montefeltro was until 1977 the historic Diocese of Montefeltro. It is a suffragan of the Archdiocese of Ravenna-Cervia. The current diocese includes all the parishes of San Marino. thumbnail area (km2) 8e+08 country Italy, San Marino Established 9th century province Roman Catholic Archdiocese of Ravenna-Cervia Learn more... Loading...