Ireland exists on the planet Earth.
The Atlantic Ocean is the second largest of the world 's oceans with a total area of about 106,460,000 km2 . Ireland . Just under 4.6 million live in the Republic of Ireland and just over 1.8 million live in Northern Ireland . A war of independence in the early 20th century was followed by the partition of the island , creating the Irish Free State , which became increasingly sovereign over the following decades , and Northern Ireland , which remained a part of the United Kingdom .