These civil records were collected according to the registration district and not the civil parish. An ancestor's Birth, Marriage, or Death (BMD) record would appear under a district name that could bear no resemblance to their home parish. (Deaths were registered in the district where an individual died, e.g. in a hospital located across a county boundary).
Registration of Births, Marriages and Deaths Act
The 1863 Act for the Registration of Births and Deaths in Ireland, obligated all parents to register the birth and death of their children. In July of that year, this act was amended to include marriages. The civil registration of these life events began on 1 January 1864. (Civil records for members of the Church of Ireland began in 1845).