My g-grandparents were both born in Ireland and emigrated to America sometime in the late 1840's. They were Roman Catholic. Luke Grace b.1817-1820 d. 1902 Cleveland Anna (Higgins) Grace b. 1822-1825 d. 1896 Cleveland
All of the U.S. Census records (including their children) through 1920 would only show Ireland as their birthplace.
No indication of county or town was ever shown on any document, so far. Even Luke's Naturalization record only shows Ireland.
In the 1930 U.S. Census, two living children showed Northern Ireland as the birthplace of their parents. I assume that they selected Northern Ireland on this Census because of the split in Ireland that occurred in 1920. I am looking for any possible link to one of the Northern Ireland counties from c.1817-1850. Maybe someone has seen these names in county or church records or family tree.