Hi
Do you know much about their emigration? Dates, the reason why they left, who they may have travelled with etc.? Generally more information was given at the port of arrival rather than the port of departure. If you knew which city they arrived at (e.g. Liverpool), this could be a good place to find more information.
Have you tried checking http://www.irishtimes.com/ancestor/browse/counties/rcmaps/mayorc.htm for the availability of records for the area?
You might try contacting the Mayo Genealogy Group http://www.ouririshheritage.org/page_id__293_path__0p4p.aspx Mayo genealogy group info
Remember to post as much information as you can regarding the people you are researching. The more information you post, the more likely it is that one of our volunteers will be able to advise or assist you.
Also include information concerning which sources you may have already used so others may further your search.
Please make sure you link anyone else in your family who is interested in their Irish heritage to our site - and indeed anyone else you know of Irish heritage.
Kind regards,
Genealogy Support
Ireland Reaching Out