St. Patrick's Cathedral in Armagh, Northern Ireland is the seat of the Catholic Archbishop of Armagh, Primate of All Ireland. It was built in various phases between 1840 and 1904 to serve as the Roman Catholic cathedral of the Archdiocese of Armagh, the original medieval Cathedral of St. Patrick having been retained by the state church, the Church of Ireland at the time of the split of the Irish Church during the Reformation.

Armagh is the county town of County Armagh and a city in Northern Ireland, as well as a civil parish. It is the ecclesiastical capital of Ireland – the seat of the Archbishops of Armagh, the Primates of All Ireland for both the Roman Catholic Church and the Church of Ireland. In ancient times, nearby Navan Fort was a pagan ceremonial site and one of the great royal capitals of Gaelic Ireland. Today, Armagh is home to two cathedrals and the Armagh Observatory, and is known for its Georgian architecture.