Northern Ireland ( , Ulster Scots: Norlin Airlann or Norlin Airlan) is a part of the United Kingdom in the north-east of the island of Ireland. It shares a border with the Republic of Ireland to the south and west. As of 2001, its population was 1,685,000, constituting about 30% of the island's total population and about 3% of the population of the United Kingdom. Since the signing of the Good Friday Agreement in 1998, Northern Ireland is largely self-governing. According to the agreement, Northern Ireland co-operates with the rest of Ireland – from which it was partitioned in 1921 — on some policy areas, while other areas are reserved for the Government of the United Kingdom, though the Republic of Ireland "may put forward views and proposals".

Irlanda del Norte (Northern Ireland, en inglés; Tuaisceart Éireann, en irlandés) es un país constituyente (constituent country) del Reino Unido, que se encuentra al nordeste de la isla de Irlanda, corresponde a la mayor parte del Ulster.