Ireland (Irish: Éire, also known as the Republic of Ireland), is a sovereign state in western Europe occupying about five-sixths of the island of Ireland. The capital and largest city is Dublin, located in the eastern part of the island, whose metropolitan area is home to around a third of the country's 4.6 million inhabitants. The state shares its only land border with Northern Ireland, a part of the United Kingdom. It is otherwise surrounded by the Atlantic Ocean, with the Celtic Sea to the south, Saint George's Channel to the south east, and the Irish Sea to the east. It is a unitary, parliamentary republic with an elected president serving as head of state. The head of government, the Taoiseach, is nominated by the lower house of parliament, Dáil Éireann.
Following the secession of most of Ireland from the United Kingdom in 1922, the then created Irish Free State remained (for the purposes of British law) a dominion of the British Empire and thus its people remained British subjects with the right to live and work in the United Kingdom and elsewhere in the Empire. The British monarch continued to be head of state.
The Republic of Ireland Act 1948 declared that Ireland may be officially described as the Republic of Ireland, and vested in the President of Ireland the power to exercise the executive authority of the state in its external relations, on the advice of the Government of Ireland. The Act was signed into law on 21 December 1948 and came into force on 18 April 1949.