Republic of Ireland ( Irish : Éire ) The bulk (five hexagon) of the island of Ireland . The island is located in the northeast of the Atlantic Ocean , adjacent to the island of Britain . It is separated from Britain by the North Sea , the Irish Sea , the Canal of St. George and the Celtic Sea . Northern Ireland , affiliated with the United Kingdom , forms the other small part of the island. Known in the Gaelic language "Ayr". It is also known as the "Emerald Island" for the beauty of its green countryside.