Ireland, also called the "Emerald Isle", is an island in the North Atlantic, separated from Great Britain by the North Channel, the Irish Sea and St. Georges Channel. It is the second largest island of the British Isles archipelago, the third-largest European one and the twentieth-largest on Earth.
Politically, Ireland is divided between the Republic of Ireland, which covers five-sixths of the island, and Northern Ireland, a part of the United Kingdom, which covers the remaining area and is located in the north-eastern part. The population of Ireland is about 6,4 million, of which fewer than 4,6 million live in the Republic of Ireland and just over 1,8 million live in Northern Ireland.
The island's geography comprises relatively low-lying mountains surrounding a central plain, with several navigable rivers extending inland, with the Shannon River being the largest one. Moors cover nearly a fifth of the state territory of the Republic of Ireland. The island has lush vegetation, a product of its mild but changeable oceanic climate, which avoids temperature extremes. Biodiversity in Ireland is relatively poor because of the last Ice Age, as there are only twenty-six extant mammal species native to Ireland.