Looking for Leahey or Lahy family

Hi  I'm looking for any information on a William Leahey ...may have been spelled Lahy...born approximately 1797...... I think he MIGHT have married a Mary Power...I know his wife's name was Mary....I am not positive about Power being her last name. I believe her birthdate was 1815. They had a son Edward who was born in 1842 and was baptized on May 16 1842. and a daughter Margaret who was born in 1839 or 1840. Margaret was my husband's great great grandmother and I am looking for any information on her, and her parents noted above. I am especially interested in any marriage records for Margaret. I don't know if she was married in Ireland or the US....but she married a Patrick Lanigan who was born between 1823 and 1828. Our family is planning a trip to,Irleand and we have been unable to,find any information on Patrick Lanigan or even where he was from.....but once I located Edward Lahys record online and noticed he was born in Tipperary I thought maybe that is also where Partick Lanigan came from because he married Edwards sister. Just trying to figure it out!