Partition of Ireland in the context of "Irish nationalism"

Northern Ireland is a part of the United Kingdom in the north-east of the island of Ireland. It has been variously described as a country, province or region. Northern Ireland shares an open border to the south and west with the Republic of Ireland. At the 2021 census, its population was 1,903,175, making up around 3% of the UK's population and 27% of the population on the island of Ireland. The Northern Ireland Assembly, established by the Northern Ireland Act 1998, holds responsibility for a range of devolved policy matters, while other areas are reserved for the UK Government. The government of Northern Ireland cooperates with the government of Ireland in several areas under the terms of the Good Friday Agreement. The Republic of Ireland also has a consultative role on non-devolved governmental matters through the British–Irish Governmental Conference (BIIG).

Northern Ireland was created in 1921, when Ireland was partitioned by the Government of Ireland Act 1920, creating a devolved government for the six northeastern counties. As was intended by unionists and their supporters in Westminster, Northern Ireland had a unionist majority, who wanted to remain in the United Kingdom; they were generally the Protestant descendants of colonists from Britain. Meanwhile, the majority in Southern Ireland (which became the Irish Free State in 1922), and a significant minority in Northern Ireland, were Irish nationalists (generally Catholics) who wanted a united independent Ireland. Today, the former generally see themselves as British and the latter generally see themselves as Irish, while a Northern Irish or Ulster identity is claimed by a significant minority from all backgrounds.

The courts of Northern Ireland are the civil and criminal courts responsible for the administration of justice in Northern Ireland: they are constituted and governed by the law of Northern Ireland.

Prior to the partition of Ireland, Northern Ireland was part of the courts system of Ireland. After partition, Northern Ireland's courts became separate from the court system of the Republic of Ireland. Northern Ireland continues to have a separate legal system to the rest of the United Kingdom. There are exceptions to that rule, such as in immigration and military law, for which there is a unified judicial system for the whole United Kingdom.

The government of Northern Ireland is, generally speaking, whatever political body exercises political authority over Northern Ireland. A number of separate systems of government exist or have existed in Northern Ireland.

Following the partition of Ireland, Northern Ireland was recognised as a separate territory within the authority of the British Crown on 3 May 1921, under the Government of Ireland Act 1920. The new autonomous Northern Ireland was formed from six of the nine counties of Ulster, being four counties with unionist majorities (Antrim, Armagh, Down and Londonderry), and Fermanagh and Tyrone two of the five Ulster counties which had nationalist majorities. In large part unionists, at least in the north east region, supported its creation while nationalists were opposed. Subsequently, on 6 December 1922, the island of Ireland became an independent dominion known as the Irish Free State but Northern Ireland immediately exercised its right to opt out of the new Dominion.

The Government of Ireland Act 1920 (10 & 11 Geo. 5. c. 67) was an act of the Parliament of the United Kingdom. The Act's long title was "An Act to provide for the better government of Ireland"; it is also known as the Fourth Home Rule Bill or (inaccurately) as the Fourth Home Rule Act and informally known as the Partition Act. The Act was intended to partition Ireland into two self-governing polities: the six north-eastern counties were to form "Northern Ireland", while the larger part of the country was to form "Southern Ireland". Both territories were to remain part of the United Kingdom of Great Britain and Ireland and provision was made for their future reunification through a Council of Ireland. The Act was passed by the British Parliament in November 1920, received royal assent in December and came into force on 3 May 1921.

The smaller Northern Ireland was duly created with a devolved government and remained in the UK. The larger Southern Ireland was not recognised by most of its citizens, who instead recognised the self-declared Irish Republic in the ongoing Irish War of Independence. The conflict resulted in the Anglo-Irish Treaty in December 1921. Under the treaty, Ireland would leave the UK (with the option for Northern Ireland to opt out and remain in the UK, which it immediately did) in December 1922 and become the Irish Free State, which would later evolve into today's Republic of Ireland. The institutions set up under this Act for Northern Ireland continued to function until they were suspended by the British parliament in 1972 as a consequence of the Troubles.

Northern Ireland is divided into six counties, namely Antrim, Armagh, Down, Fermanagh, Londonderry and Tyrone. Six largely rural administrative counties based on these were among the eight primary local government areas of Northern Ireland from its 1921 creation until 1973. The other two local government areas were the urban county boroughs of Derry (geographically part of the County of Londonderry) and Belfast (geographically split between the counties of Antrim and Down).

The six counties date from the Kingdom of Ireland; five were created between 1570 and 1591 in the Tudor conquest of Ireland, while county Londonderry dates from 1613 and the Plantation of Ulster. The total number of counties in the island of Ireland is 32, with Northern Ireland and the Republic of Ireland often respectively called "the Six Counties" and "the Twenty-Six Counties", especially by Irish nationalists opposed to the partition of Ireland. The 1898–1973 administrative counties were subdivided into county districts. The two-tier county/district system was replaced with a single-tier of "districts", numbering 26 in 1973 and rationalised into 11 in 2015. The areas corresponding to the six counties and two county boroughs remain in use for some administrative purposes, and the six historic counties retain a popular identity.

Unionism in Ireland is a political tradition that professes loyalty to the crown of the United Kingdom and to the union it represents with England, Scotland and Wales. The overwhelming sentiment of Ireland's Protestant minority, unionism mobilised in the decades following Catholic Emancipation in 1829 to oppose restoration of a separate Irish parliament. Since Partition in 1921, as Ulster unionism its goal has been to retain Northern Ireland as a devolved region within the United Kingdom and to resist the prospect of an all-Ireland republic. Within the framework of the 1998 Belfast Agreement, which concluded three decades of political violence, unionists have shared office with Irish nationalists in a reformed Northern Ireland Assembly. As of February 2024, they no longer do so as the larger faction: they serve in an executive with an Irish republican (Sinn Féin) First Minister.

Unionism became an overarching partisan affiliation in Ireland late in the nineteenth century. Typically Presbyterian agrarian-reform Liberals coalesced with traditionally Anglican, Orange Order allied, Conservatives against the Irish Home Rule Bills of 1886 and 1893. Joined by loyalist labour, on the eve of World War I this broad opposition to Irish self-government concentrated in Belfast and its hinterlands as Ulster unionism and prepared an armed resistance—the Ulster Volunteers.

Ulster Protestants are an ethnoreligious group in the Irish province of Ulster, where they make up about 43.5% of the population. Most Ulster Protestants are descendants of settlers who arrived from Great Britain in the early 17th century Ulster Plantation. This was the settlement of the Gaelic, Catholic province of Ulster by Scots and English speaking Protestants, mostly from the Scottish Lowlands and Northern England. Many more Scottish Protestant migrants arrived in Ulster in the late 17th century. Those who came from Scotland were mostly Presbyterians, while those from England were mostly Anglicans (see Church of Ireland). There is also a small Methodist community and the Methodist Church in Ireland dates to John Wesley's visit to Ulster in 1752. Although most Ulster Protestants descend from Lowland Scottish people (some of whose descendants consider themselves Ulster Scots), many descend from English, and to a lesser extent, from Irish, Welsh and Huguenots.

Since the 17th century, sectarian and political divisions between Ulster Protestants and Irish Catholics have played a major role in the history of Ulster, and of Ireland as a whole. It has led to bouts of violence and political upheaval, notably in the Irish Confederate Wars, the Cromwellian conquest of Ireland, the Williamite War, the Armagh disturbances, Irish Rebellion of 1798, the Irish revolutionary period, and the Troubles. Today, the vast majority of Ulster Protestants live in Northern Ireland, which was created in 1921 to have an Ulster Protestant majority, and in the east of County Donegal. Politically, most are unionists, who have an Ulster British identity and want Northern Ireland to remain part of the United Kingdom.

Southern Ireland (Irish: Deisceart Éireann, pronounced [dʲɛʃcəɾˠt̪ˠ ˈeːɾʲən̪ˠ]) was the larger of the two parts of Ireland that were created when Ireland was partitioned by the Government of Ireland Act 1920. It comprised 26 of the 32 counties of Ireland or about five-sixths of the area of the island, whilst the remaining six counties, which occupied most of Ulster in the north of the island, formed Northern Ireland.

The Act of 1920, which became effective on 3 May 1921, was intended to create two self-governing territories within Ireland, each with its own parliament and governmental institutions, and both remaining within the United Kingdom of Great Britain and Ireland. It also contained provisions for co-operation between the two territories and for the eventual reunification of Ireland. However, in the 1921 elections for Southern Ireland's House of Commons, Sinn Féin candidates won 124 of the 128 seats (all candidates were unopposed and no actual polling occurred), and ignored the parliament, assembling instead as the Second Dáil. The House of Commons of Southern Ireland—consisting of the four unionist members—met only once, while the Senate only met twice. Continuing unrest resulted in the Anglo-Irish Treaty and the Provisional Government, which administered Southern Ireland from 16 January 1922 to 5 December 1922: effectively a transitional administration for the period between the ratifying of the Anglo-Irish Treaty and the establishment of the Irish Free State. Its legitimacy was disputed by the Anti-Treaty delegates to Dáil Éireann.