A bishop's borough or bishop borough was a pocket borough in the Irish House of Commons where the patron who controlled the borough was the bishop for the time being of the diocese of the Church of Ireland whose cathedral was within the borough. All bishops were themselves ex officio members of the Irish House of Lords. Three bishop's boroughs (Old Leighlin, Clogher, and St Canice or Irishtown) were disenfranchised by the Acts of Union 1800, and their bishops at the time applied for the standard £15,000 compensation due to patrons of disenfranchised boroughs; however, the Commissioners rejected these claims, and awarded the money to the Board of First Fruits. Armagh City, the Archbishop of Armagh's borough, remained enfranchised at Westminster and under the archbishop's control until the Irish Reform Act 1832. Although Cashel and Tuam were originally archbishops' boroughs, they passed to lay patrons in the eighteenth century.
Even before seats in the House of Commons were greatly valued, the Irish bishops had interested themselves in the municipal corporations and in municipal politics. In 1680 John Vesey, archbishop of Tuam, wrote to Ormonde to present Alderman Thomas Cartwright, the newly elected mayor of Galway, "as a person very well qualified for that trust, on account of his conformity to the Church, and consequently his loyalty to the King." "And indeed," added the archbishop, "I must needs say, with much comfort, for the few English Protestants there incorporated, that they seem to be very well principled, all very uniform in their public devotions, and manageable on any occasion readily for his Majesty's service."