Subscription site RootsIreland has an extensive collection of transcriptions of locally held Catholic parish registers from almost all of the island. Search results links to NLI images where relevant.
There’s no need to pay for Catholic records from Dublin City, County Kerry or southwest County Cork: It’s free to search these and view record images on the Irish Genealogy website.
Although most Irish (including those who immigrated to the United States) were Catholics, their church records can be hard to find. Penal Laws—legislation against religious groups that refused to join the Church of Ireland—made proper recordkeeping difficult and potentially dangerous for priests and their congregations. As a result, Irish Catholic baptism, marriage and burial registers were inconsistent, and some didn’t survive.
In general, the oldest Catholic church records hail from the more prosperous and Anglicized eastern half of the island. Registers for poorer and more densely populated parishes in the west and north often don’t start until the mid-19th century. Sadly, these poorer areas also supplied the greatest numbers of passengers on emigrant ships. If you’re lucky enough to find your ancestors in Irish Catholic registers, you may find this valuable information:
Baptism: ceremony date, child’s name, father’s full name, mother’s first name and maiden name, names of any godparents (sponsors, usually indicated by an SS), and parents’ residence
Marriage: bride’s and groom’s first names, surnames and places of residence; names and occupations of couple’s fathers; and names of officiating priest and two witnesses
Burial: name of the deceased and date of interment