Looking for my great-great-grandfather, John Kelly.

John Kelly was born in about 1841.  Most records say that he was born in Ireland; some say Guysborough, Nova Scotia.  His parents were Edward Kelly (or Kelley) and Ellen Powers.  He fished between Guysborough and Gloucester, Massachusetts.  His parents may have taken him to Nova Scotia as a child, or they may have remained behind in Ireland.  He met and married my great-great-grandmother in Gloucester.  I realize that they are pretty common names, but I am hoping that having both their names may help come up with a marriage record.  I have not found one, however, on the US version of ancestry.  Can anyone help me find where in Ireland they came from?

Thank you in advance, Anne Tierney Goldstein