Hi Patrick,
Thank you for your message. I hope that someone with information makes a connection with you.
If you look at the map a the following link you will see that the Catholic parishes of Ballinhassig/Clountead/Inishannon are all in very close proximity to each other so it is very likely that the family lived in that general area of Cork:
http://www.irishtimes.com/ancestor/browse/counties/rcmaps/corkswrc.htm
These Catholic parishes incorporate the civil parishes of:
Brinny, Inishannon, Knockavilly, Leighmoney, Templemichael, Ballinaboy, Dunderrow, Ballymartle, Clontead and Cullen.
Using Griffith?s Valuation (1848-64) and these civil parish names you can try and find some possible records and more exact places of residence for John:
http://www.askaboutireland.ie/griffith-valuation/index.xml?action=nameSearch
You could also try searching the earlier land record called the Tithe Applotment Books for any Leary?s in Desertserges around the time of John?s birth:
http://titheapplotmentbooks.nationalarchives.ie/search/tab/home.jsp
Some other websites that you may find helpful 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
Irish Times: http://www.irishtimes.com/ancestor/index.htm
Irish Genealogy Tool kit: http://www.irish-genealogy-toolkit.com/
West Cork Genealogy: www.westcorkgenealogy.ie
Cork Past and Present: www.corkpastandpresent.ie
Failte Romhat: www.failteromhat.com
Best wishes,
Genealogy Support