Hi Vicki, thanks for your message.
I know that it can sometimes be hard to gather information, but is there anything else about Mary that you can post, particularly in relation to a placename? Is there any documentation with a townland, parish or even village/town mentioned? If you could find something like this it would really help you in your search for information. Once you have a parish you will know where to look for Church Records.
You say that she emigrated to Canada. Do you know anything abut her emigration? Generally more information was givenat the port of entry rather than that of departure. If you knew what port she landed at it may help you find information-and perhaps even an exact place of origin. The Libraries and Archives of Canda may help you in your search for immigration records and this can be found here:
http://www.collectionscanada.gc.ca/index-e.html
Have you tried searching the census records for 1901 and 1911? Again, however it may be hard to narrow down the search without a parish name. You can search the census records here:
http://www.census.nationalarchives.ie/search/
Some other websites that may be of benefit or have some useful tips for you are the Irish National Library and The National Archives of Ireland. These can be found at http://www.nli.ie/en/family-history-introduction.aspx and http://www.nationalarchives.ie/genealogy1/genealogy-records/introduction/ respectively.
You could also do a search at https://familysearch.org/
I hope that some of these links helps you in your search. Remember to post any new information that you come across as the more information you post, the more likely it is that one of our volunteers will be able to advise or assist you.
Kind regards,
Genealogy Support
