I don't know if this list is still in use but am going to post my message here and see what happens.
My grgr grandfather, Patrick Clerkin apparently came to this country around 1847-8. He was found in the 1850 census for Botetourt Co., VA., age listed as 21. Family lore says he came over with a sister, Mary. In Dec. 1850 he married Martha J. Cahoon and had the following children:
Ellen, b. 1852 (my gr grandmother Mary Margaret Matthew Anne Patrick William Andrew Lewis
None of these names, with the exception of Andrew, are from the Cahoon line which makes me believe they were relatives/siblings of Patrick's left in Ireland. I think he may have emigrated from County Monaghan as that seems to be where most of the Clerkins are/were. Can anyone help me on this line in Ireland?