The archdiocese covers an area of 10,899 square miles (28,230 km2) and spans the historic county of Herefordshire and eastern South Wales.

The metropolitan see of the previous archdiocese was in the city of Cardiff where the archbishop's seat was located at the Metropolitan Cathedral Church of St David and the seat of the Diocese of Menevia was in St Joseph's Cathedral, Swansea.

He was originally the 8th and last Archbishop of Cardiff and 12th and last Bishop of Menevia, who was appointed by the Holy See on 27 April 2022 and installed at St David's Cathedral, Cardiff on 20 June and St Joseph's Cathedral, Swansea on 23 June 2022.

[4] The Welsh District covered all of the principality of Wales and the English county of Herefordshire.

[4][6] Following further reorganisation of the Catholic Church in Wales in 1916, the diocese of Newport was elevated to an ecclesiastical province and changed its name to the archdiocese of Cardiff.