Gortnahoe is in north Tipperary, only a few kilometres from Urlingford. The parish records date from 1805. I couldn't locate Gortnahoe on rootsireland.ie (subscription site) but the parish registers are at this link: https://registers.nli.ie/registers/vtls000632725#page/1/mode/1up. You may find something there (if you have time to look!!).
Best wishes, Kieran