Thank you for your message.
Do you have any other information that you can share? Do you know any important dates relating to Mary's life, such as birth/marriage/emigration dates? If you have a timeframe it will help determine what records are relevant to your search. Did Mary emigrate? If so, what do you know about her emigration? Generally more information was given at the port of arrival rather than that of departure. If you knew what city she arrived in it may be a place to get more information.
You can try searching Church records for information on Mary. Most Catholic records are held locally. One website which may be helpful is the irishtimes. Here they give an overview of what records are available in specific parishes. For Howth/Baldoyle, follow this link:
You could also do a check in the land records pertaining to Ireland in the 19th century-if the dates are appropriate. There are two:
The Tithe Applotment Books (1823-1838) http://titheapplotmentbooks.nationalarchives.ie/search/tab/home.jsp
Griffith's Valuation (1848-1864) http://www.askaboutireland.ie/griffith-valuation/
You can also search the 1901/1911 census records online at http://www.census.nationalarchives.ie/search/
Some other useful websites are:
The National Archives of Ireland http://www.nationalarchives.ie/genealogy1/genealogy-records/introduction/
The National Library of Ireland http://www.nli.ie/en/family-history-introduction.aspx
The National Archives UK ? genealogy search: http://www.nationalarchives.gov.uk/records/looking-for-person/
The Public Records Office of Northern Ireland http://www.proni.gov.uk/index/family_history.htm
Family Search: https://familysearch.org/
I hope that this helps. Remember to post as much information as you can with regard to 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 be patient - as our programme has only begun to rollout across the island of Ireland and volunteers in some areas may not yet be organized.