Another famous one is "Ireland, Boys, Hurrah", which you should find in the Digitrad; in some American Civil War battle or other (Bull Run? Gettysburg? People tell me, but I've never seen the sites, so I forget instantly) huge numbers of the soldiers on both sides were Irish, many just off the boat. They were camped on either side of the river the night before the battle and when one side started singing:

"Deep in Canadian woods we've met, from one bright island flown..."

the boys on the other side took up the verse, and as one verse finished on one side of the river they could hear the beginning of the next rolling back, so great were the numbers of men singing.

Another thing you might be interested in - there's a new album out by a band called, I think, Sons of Erin, which consists of historical songs in relation to Irish America: Clear the Way is the name, I think. ("Clear the Way" is the English for "Fagaim Bealach" - the battle-cry of the Irish troops wherever they fought; it would be better rendered as "Give me room".)

Here's a website where you can find the CD:

http://www.dararecords.com/imn/images/d_warfield_cleartheway_360.jpg