Northern Ireland is a part of the United Kingdom in the north-east of the island of Ireland, variously described as a country, province or region. Northern Ireland shares a border to the south and west with the Republic of Ireland. In 2011, its population was 1,810,863, constituting about 30% of the island's total population and about 3% of the UK's population. Established by the Northern Ireland Act 1998 as part of the Good Friday Agreement, the Northern Ireland Assembly holds responsibility for a range of devolved policy matters, while other areas are reserved for the British government. Northern Ireland co-operates with the Republic of Ireland in some areas, and the Agreement granted the Republic the ability to "put forward views and proposals" with "determined efforts to resolve disagreements between the two governments".
Northern Ireland was created in 1921, when Ireland was partitioned between Northern Ireland and Southern Ireland by the Government of Ireland Act 1920. Unlike Southern Ireland, which would become the Irish Free State in 1922, the majority of Northern Ireland's population were unionists, who wanted to remain within the United Kingdom.