St Muredach's Cathedral is the cathedral church of the Roman Catholic Diocese of Killala in Ireland. It is located on the bank of the River Moy in Ballina, County Mayo. The cathedral was built in 1834, in a Victorian Gothic style. It is also the parish church of the parish of Kilmoremoy. It is the Cathedral Church of the Diocese of Killala. Construction began in 1827. The stone was quarried locally and the roof and ceiling were completed before the Great Famine of 1845. The spire was completed in 1855 and by 1875 the organ had been installed.