My ggaunt, Nora Finnegan, of Brosna married a Corneilous Sullivan (I believe also from Brosna) around 1880 in Brosna. Corneilous Sullivan came to San Francisco in 1884 and Nora came 3 years later in 1887 with their 3 young children - John, Nora and Elizabeth. Corneilous Sullivan was born around 1859 and died in San Francisco in 1921. His obituary states he was survived by a sister, Elizabeth (who was married to John Callaghan and who were then living in San Francisco).
If any of the above connects with your family history please let me know.