Northern Ireland is part of the United Kingdom and covers 5,459 square miles (14,139 km²) in the northeast of the island of Ireland, about a sixth of the total area of the island. It has a population of 1,685,000 (April 2001) — between a quarter and a third of the island's total population. It consists of six counties situated within the province of Ulster, and in the UK is generally known as one of its four Home Nations, forming a constituent country of the United Kingdom. Some of these terms have controversial implications in relation to political ideologies concerning the constitutional status of Northern Ireland.

As an administrative division of the United Kingdom, Northern Ireland was defined by the Government of Ireland Act, 1920, and has had its own form of devolved government in a similar manner to Scotland and Wales. The Northern Ireland Assembly is, however, currently in suspension.

Northern Ireland has been for many years the site of a violent and bitter ethno-political conflict between those claiming to represent Nationalists (who are predominantly Catholic and want it to be unified with the Republic of Ireland) and those claiming to represent Unionists (who are predominantly Protestant and want it to remain part of the United Kingdom). Unionists are in the majority in Northern Ireland, though Nationalists do represent a significant minority. The campaign of violence has become known popularly as The Troubles. The majority of both sides of the community have had no actual association with the violent campaigns waged, and most have not supported the violent representatives of their respective communities. Since the signing of the Belfast Agreement in 1998, many of the major paramilitary campaigns have either been on ceasefire or have declared their "war" to be over.