looking for Charles O'Neill who married Bridget Higgins in Loughrea 1844

I am looking for information on this couple:  Charles O'Neill and Bridget Higgins who married 12Feb1844 in Loughrea,Galway.  I am not certain this couple are my 3xgreat-grandparents but it is the best lead I have.  I know my great-grandparents emmigrated to USA before 1850, first to Pennsylvania and then Ohio.  Two children were born in Pennsylvania about 1849 and 1851, named Thomas and Charles.  Later they had MaryAnn,b.1852,Ohio, Belle(Isabel)b.1854,Ohio,Bridget,b.1859,Ohio,John,b.1861,Ohio, and Barney,b.1864,Ohio.  They lived in Ironton,Ohio and the father Charles was a miner.  I do not know the names of the parents or any siblings of this couple unfortunately.

Any help or clues to learn more would be very appreciated.  I will be visiting Ireland in July and will have a day or two to spend in Galway doing research.  Any suggestions for furthering my research also appreciated.

Thank you,

Carolyn