Searching for history of my Great Grandfather, born in Galway in October of 1840. I don't know his parents name. He married Bridget Thornton, but in England before immigrating to the US in 1873.
Nancy,
If you get a copy of John & Bridget’s marriage certificate it should tell you a bit more about them. Notably their father’s names and occupations which may make tracing them easier in Ireland. What looks likely to be their marriage was registered in Wolverhampton, April – June 1870 Volume 6b page 732.
You can order a copy of that certificate from the English General Register Office.