Honorah Clarke

Mary,

You could try checking the land records called the Tithe Applotment Books (1823-38) or the later Griffith's Valuation (1848-64). The Tithe Applotment Books (1823-38): Microfilm copies of the books for all of Ireland are available at the National Archives of Ireland (NAI) http://www.nationalarchives.ie/genealogy1/genealogy-records/tithe-applotment-books-and-the-primary-griffith-valuation/ or the Church of Latter Day Saints (LDS). Griffith's is freely available here: www.askaboutireland.com or here: www.failteromhat.com Failte Romhat has lots of other useful links you could try looking at. 

Church of Ireland parish registers for the period up to 1870 are public records. Registers are available for about one third of the parishes, however many were destroyed in the Public Records Office in Dublin in 1922. Most are still held by the local clergy, although some are in the National Archives of Ireland and others are in the Representative Church Body Library in Dublin. A list of all surviving registers is available in the National Archives. http://ireland.anglican.org/about/42 and http://www.nationalarchives.ie/. Some catholic registers are held in the National Library of Ireland http://www.nli.ie/en/parish-register.aspx . It might be worth while to contact the local parish offices for further assistance. 

Also one very helpful group in the area are the Mayo Genealogy Group. You can contact them via Facebook at https://www.facebook.com/groups/clansofmayo/ .

Some records for Co Mayo are available for a fee from http://mayo.rootsireland.ie/.

I wish you the best of luck with your research.

Genealogy support