Roman Catholic Diocese of Argyll and the Isles Tags: Clerical Administrative Region, Diocese.The Roman Catholic Diocese of Argyll and the Isles (Latin Diocesis Ergadiensis et Insularum) is an ecclesiastical territory or diocese of the Roman Catholic Church in Scotland in the Province of Saint Andrews and Edinburgh. point area (km2) 3.108e+10 country Scotland Established 4 March 1878 jurisdiction Diocese province Roman Catholic Archdiocese of St Andrews and Edinburgh territory Outer Hebrides, Argyll and Bute, Highland (council area), Isle of Arran latitude 56.4167 longitude -5.46667 Learn more... Loading...