Joan, My GGGgrandparents, John and Margaret Devlin lived in the Ulster Co., NY, area for a little while. Am not sure how long. Their son, my GGgrandfather, Francis Henry Devlin, was born in Glascoe in March 1848. I just recently learned that Margaret (mainden name may be Dillon?) was born in County Roscommon, that they married sometime around 1844 and went to Canada before coming to the States. They ended up eventually in Pennsylvania but I think there may have also been a short stay in Maryland.
Anything ring a bell here? I found them in the 1850 census in Saugerties, written page 225, printed page 121a. Last name spelled as "Davlin".