Ireland, satellite image. North is at top. Green areas are vegetated. Grey areas are urban. Ireland is a large island in western Europe. It borders Great Britain to the east and the Atlantic Ocean to the west. Politically it is divided into Northern Island, which is part of the United Kingdom and the Republic of Ireland in the south. The large lake in the north is Lough Neagh. to the east of Lough Neagh is Belfast, the capital city of Northern Ireland. Dublin, the capital of the Republic of Ireland is half way along Ireland's east coast.