My grandfather, Gorman Payne McMillan (1894-1977) , was named "Gorman" (his grandmother's maiden name), "Payne" (his mother's maiden name) and "McMillan" his father's surname. He left genealogical notes and letters indicating that his maternal grandmother Eliza Gorman (c1832-1863) had come from Ballyheigue with her mother, Johanna (Sullivan) Gorman and at least two brothers named John and William. I believe Eliza's father, John Gorman, had died before the family immigrated or while the family lived in Boston, MA where they first landed. There is no record of the father in western NY where the family later settled.
Eliza Gorman married George E. Payne in Victor, Ontario Co, NY on 15 May 1855. They soon headed west to Iowa where they lived in a sod house and Eliza gave birth to 4 daughters; Phoebe Ann (b. 1856), Hannah J. (b.1857), Maud L. (b. 1859) and Eliza Weltha (b. 1861) my great grandmother. In Jan 1863, Eliza gave birth to a fifth daughter and she and the baby died. I have not found her grave, but believe she is buried in Iowa. She packed a lot of living into her 31 years; traveled thousands of miles, homesteaded on the American prairie and left four daughters who all had children of their own.
Eliza Gorman's brothers, John and William, both served in the American Civil War. 
John Gorman enlisted Aug 1862 in the 126th Reg. NY, Company H [Orrin J. Herendeen, Comm.] John survived the battles of Gettysburg, Auburn Ford, Bristoe Station, Morton's Ford, Wilderness, Po River, Spotsylvania, Totopotomoy, Cold Harbor, Petersburg, Weldon R.R., Deep Bottom and Ream's Station (25 Aug 1864) where he was taken prisoner. He died 1865 in Andersonville Prison and is buried there. His widow married William Decke of Detroit. John's son William Gorman (b. 1862) was renamed William Decke.
William Gorman enlisted 4 Sep 1862 in Bemis' Artillery Battery, NY and was discharged at the end of the war.
Any help tracing Eliza Gorman's family in Ballyheigue would be greatly appreciated! Kathleen Wagner