Many of our Civil War soldiers who came out west, decided they would stay in NM and so they did and they got married and so on. I've been trying to research a Gerard Stack from Hacker's Creek, West Virginia for some time now and we've hit some adobe walls. Recently at the Salt Lake Christmas Tour, I found out that the www.rootsireland.ie have opened up their church records for free. I was very impressed and found that there are some 54 Gerard Stack's. One of them has to be ours.
The second best place to find material on Ireland is at www.familysearch.org. Go to Europe and then Ireland, there are a bunch of free databases and they keep adding to them. I keep checking this one about one a month.
Good luck hunting the Irish.