My great grandfather Patrick Horan was born in Castlebar,about 1837-40. I think it was the town land of Cloonkeen since I found a birth record for his sister Bridget on January 18, 1843,child of Michael Horan and Winny White. There is also a record for Michael Horan born in 1851 to Michael Horan and Winifred White. I cannot find any other records.
Griffiths Valuation for 1857 lists Michael Horan in Cloonkeen where he lived on plot 1f, and farmed land in common with other nearby farmers. A Thaddeus Horan was on plot 2, so possibly a relation.
http://www.askaboutireland.ie/griffith-valuation/index.xml?action=placeSearch
One Horan farm still there in 1901:
http://www.census.nationalarchives.ie/pages/1901/Mayo/Cloonkeen/Cloonkeen/1584706/
If you get Patrick’s civil marriage certificate, it should tell you his father’s name. I think his marriage may have been registered in Castlebar Jan – Mar 1891 Vol 4, page 79.
I have Patrick's he married in Wigan,England in 1859 and his father is listed as Michael Horan,farmer. His mother Winifred died in Wigan in 1860 and list her occupation as wife of Michael Horan,farmer.
Also, I know for sure that his parents names were Michael Horan and Winifred White as it was on marriage record and death certificates here in the states for Patrickand his sister Bridget.
Beyond what you have, there’s probably not a lot more that you can obtain on the family. I searched for a will for Michael Horan but he didn’t leave one in Ireland. Or at least not one that required probate. You could check with the Valuation Office in Dublin to see when he ceased to be the occupant of the Clonkeen farm (and who replaced him). That will probably tell you when he died and who he left it to. (Usually the eldest son).That's about all I can suggest.