"Ireland's" is the possessive form of Ireland, used before a noun to show ownership or association. It describes something belonging to, originating from, or relating to the country of Ireland.
Was it for this the wild geese spread The gray wing upon every tide For this that all that blood was shed, For this. Edward Fitzgerald died, And Robert Emmet and Wolfe Tone, All that delirium of the brave Romantic Ireland's dead and gone, It's with O'Leary in the grave. William Butler Yeats
You that would judge me, do not judge alone this book or that, come to this hallowed place where my friends' portraits hang and look thereon; Ireland's history in their lineaments trace; think where man's glory most begins and ends and say my glory was I had such friends. William Butler Yeats
The cup of Ireland's misery has been overflowing for centuries and is not yet half full. Boyle Roche
We warned that WBC has had lots of experience with Ireland's militant sodomite citizenry, steeped for many decades in ignorant, blind idolatrous Catholicism, belching out their vile fagspeak, slander and blasphemy against God and His word. Fred Phelps
If the potato misses, Ireland's beaten. Irish Proverb
England's difficulty is Ireland's opportunity. Latin Proverb