 <unk> , Ireland is divided between the Republic of Ireland ( officially named Ireland ) , which covers five @-@ <unk> of the island , and Northern Ireland , which is part of the United Kingdom , in the northeast of the island . In 2011 the population of Ireland was about 6 @.@ 4 million , ranking it the second @-@ most populous island in Europe after Great Britain . Just under 4 @.@ 6 million live in the Republic of Ireland and just over 1 @.@ 8 million live in Northern Ireland . 
