The Bishop of Derry is an episcopal title which takes its name after the city of Derry in Northern Ireland. In the Roman Catholic Church it remains a separate title, but in the Church of Ireland it has been united with another bishopric.
The bishopric has its origin in the Columban abbey of Derry, founded by the abbots of Iona in the sixth century. By the High Middle Ages, the monastery of Derry was one of the chief monasteries of the Columban familia and its abbots often bore the title Comarbai Coluim Cille, successor of Saint Columba.
The episcopal diocese emerged from the reorganisation of the Irish church in the twelfth century. The see was founded to cover the lands of the Cenél nEógain (i.e. Tyrone). It was fixed first at Ardstraw, then at Maghera (Machaire Rátha Lúraigh – the plain of Lurach's fort). The Irish annalists commonly styled the bishops of this area 'bishop of Cenél nEógain'. Bishop Germanus, called in Irish Gilla in Choimded Ó Cerballáin, obtained sanction from Pope Innocent IV for the see to be transferred to Derry in 1254.
Following the Reformation, there are parallel apostolic successions. In the Church of Ireland, Derry continued a separate see until 1834 when it amalgamated with Raphoe and became the united bishopric of Derry and Raphoe.
In the Roman Catholic Church, the title is still a separate bishopric. At present the see is vacant. The most recent incumbent was The Most Rev. Dr. Séamus Hegarty, D.D., Lord Bishop of Derry, whose resignation was accepted by the Holy See on 23 November 2011.