Northern Ireland is one of the four constituent nations of the United Kingdom, located in the northeast of the island of Ireland. It limits to the south and west with the Republic of Ireland, to the north with the North Channel and to the east with the Irish Sea, which separates it from the island of Great Britain. The territory of Northern Ireland covers 14 130 km², and its estimated population in 2017 is 1 870 451 inhabitants, which is equivalent to one third of the total of the island and 3% of the British people. The capital and most populous city is Belfast.
It was founded in 1921 by the Parliament of the United Kingdom, in application of the Act of Government of 1920 that supposed the partition of Ireland in two entities: Northern Ireland and South Ireland The North is formed by six counties that conform two thirds of the historical province of Úlster. When the Irish of the South proclaimed the creation of the Irish Free State, the Northern Irish parliament expressed its desire to remain under British sovereignty. On the Northern Irish population there are two religious groups: a majority of Protestants, many of whom are descendants of the colonization of Ulster, and a significant minority of Catholics, in turn, the inhabitants are divided between those who support the union with the United Kingdom and those who advocate integration in Ireland. The history of the region in the 20th century has been marked by clashes between unionists and republicans.
The outbreak in 1968 of the conflict in Northern Ireland plunged the Ulster into a spiral of violence that was not resolved until three decades later.: the signing of the Good Friday agreement in 1998 has laid the foundations of a new government in which Catholics and Protestants share power.