Republic of Ireland–United Kingdom border
Originally intended as an internal boundary within the United Kingdom of Great Britain and Ireland, the border was created in 1921 under the United Kingdom Parliament's Government of Ireland Act 1920. Prior to this, a separatist Irish parliament had been established in Dublin, which did not recognise the Government of Ireland Act, and was actively engaged in the Irish War of Independence. The Act was intended to deliver Home Rule in Ireland, with separate parliaments for Southern Ireland (which included three of the nine counties of Ulster) and Northern Ireland. Six of the thirty-two counties of Ireland were assigned to Northern Ireland, and the rest of Ireland comprising 26 counties to Southern Ireland.
Administrative geography of the United Kingdom
Northern Ireland was the first part of the British Isles to have a devolved government, under the Government of Ireland Act 1920, and that continued until the Parliament of Northern Ireland was suspended in 1972. After a period of direct rule by the Westminster government and some abortive attempts at reinstating devolved government during the Troubles, the present-day Northern Ireland Assembly was established in 1998, and is currently in operation following a number of periods of suspension. The complex history of Northern Ireland has led to differing views as to its status. The term "Province" is often used by unionist and British commentators to refer to Northern Ireland, but not by nationalists.