The Stankards

I am searching for the birthplace of my great great grandfather William Stankard and his wife Ellen Taylor.  They were born abt. 1815.  William had a brother Thomas who married Isabella Brown.  William and Ellen immigrated to the USA in 1849-1850.

  I have been contacted by Stankards who told me they were from Athenry or Kiltullagh.  How can I found out what parish my great great grandfather came from?  Does parishes have records that go back that far?  Are there Stankards living in Athenry or Kiltullagh today?

Any information that can be verified would be much appreciated.  Thank you.