My father's name was Peter Joseph Gartlan of Drumgoolan, Dundalk, Co Louth, (d. 1995 in Ventura, CA) His father was Patrick Gartlan of Donaghmoyne Parish, died in the early 1940's and is buried at St. Patrick's Cathedral in Dundalk, Co. Louth. His father, John Gartlan of Killabrick, Co. Louth was born in 1865 (I think), , his father was Peter Gartlan, died 1790 and is buried in Donaghmoyne Cemetary in Co. Louth.
I had several distant Byrne cousins from Drogheda. Thomas Byrne, Mary Byrne, lived on Bolton Street and are buried in the cemetary in Navan, along with the Corry family.
I still have numerous Gartlan first cousins in Carrickmacross, Co. Monaghan, and in Louth Village as well.
Good luck on your search