List of parliamentary constituencies in Northern Ireland

1801 to 1832 (22 MPs)

1832 to 1885 (29 MPs)

1885 to 1918 (25 MPs)

1918 to 1922 (30 MPs)

   Irish Unionist    Independent Unionist    Labour Unionist    Sinn Féin

1922 to 1950 (13 MPs)

  Ulster Unionist   Ulster Progressive Unionist   Independent Unionist   New Party   Northern Ireland Labour   Independent Labour   Federation of Labour   Irish Labour   Nationalist Party

1950 to 1983 (12 MPs)

Periodic boundary reviews commenced in 1947.^[5][6] The elections at which these were implemented are tagged with diamond suit characters, ♦.

The 1st Periodic Review boundary map can be viewed on the ARK elections website. Changes in the 2nd review were relatively minor.^[7]

Notes:

1. The constituency was won by Philip Clarke of Sinn Féin, but he was unseated on petition on the basis that his criminal conviction (for Irish Republican Army activity) made him ineligible. Instead, the seat was awarded to the Ulster Unionist Party (UUP) candidate.
2. The seat was originally won by Tom Mitchell of Sinn Féin, but Mitchell was subsequently unseated upon petition, on the grounds that his terrorist convictions made him ineligible to sit in Parliament. The seat was awarded to Charles Beattie of the UUP. However, Beattie in turn was also found ineligible to sit due to holding an office of profit under the crown, triggering a further by-election.
3. Original winner of the 1950 election in that seat, James Godfrey MacManaway (UUP), disqualified due to being a clergyman. Teevan won the subsequent by-election

1983 to present (17, then 18 MPs)

3rd and 4th Review boundary maps can be viewed on the ARK elections website: 1983, 1997.

  Alliance Party   Democratic Unionist   Independent   Sinn Féin   Social Democratic and Labour   Traditional Unionist Voice   UK Unionist Party   Ulster Popular Unionist   Ulster Unionist

¹Paisley Jr was suspended from the DUP between July and November 2018.

2025–present

Following the abandonment of the Sixth Periodic Review (the 2018 review), the Boundary Commission for Northern Ireland formally launched the 2023 Review on 5 January 2021. In accordance with the provisions of the Parliamentary Constituencies Act 2020, the number of constituencies allocated to Northern Ireland was unchanged, at 18.^[8] Initial proposals were published on 20 October 2021 and, following two periods of public consultation, revised proposals were published on 17 November 2022. Final recommendations were published on 28 June 2023.^[9][10]

Under the recommendations, the following constituencies for Northern Ireland came into effect at the 2024 general election:^[11]

Belfast South and Mid Down is a new constituency, replacing the former Belfast South constituency which had a much smaller area. All of the others have undergone boundary changes, primarily to bring the electorate within the range of 69,724 to 77,062 as required by the Parliamentary Constituencies Act 1986, as amended in 2020.^[13]

2010–2025

Under the Fifth Periodic Review, the following configuration of constituencies was adopted in 2008.^[14][15] They were used in four general elections: 2010, 2015, 2017 and 2019, and also in four Assembly elections: 2011, 2016, 2017 and 2022.

1997–2010

Under the Fourth Periodic Review, the following configuration of constituencies was adopted in 1995.^[16] They were used in three general elections: 1997, 2001 and 2005, and also in four Northern Ireland-wide elections: the Forum election in 1996, and the Assembly elections in 1998, 2003 and 2007.

1983–1997

Under the House of Commons (Redistribution of Seats) Act 1979, the number of seats permitted for Northern Ireland was increased from 12 to "not greater than 18 or less than 16".^[17] This followed the abolition of the Parliament of Northern Ireland under the Northern Ireland Constitution Act 1973.

Under the Third Periodic Review, the following configuration of constituencies was adopted in 1982, with an increase from 12 to 17 constituencies.^[18] They were used in three general elections: 1983, 1987, and 1992.

1974–1983

Under the Second Periodic Review, the following configuration of constituencies was adopted in November 1970, after the general election earlier that year.^[19] They were used in three general elections: February 1974, October 1974, and 1979, and also in three Northern Ireland-wide elections: the 1973 Assembly election, the 1975 Constitutional Convention election, and the 1982 Assembly election.

1950–1974

Under the Representation of the People Act 1948, the following configuration of constituencies was adopted.^[20] They were used in seven general elections: 1950, 1951, 1955, 1959, 1964, 1966 and 1970.

The First Periodic Review, which reported in 1954 and took effect at the 1955 United Kingdom general election, made no changes to the number or boundaries of Northern Ireland constituencies.

The introduction of these constituencies accompanied the abolition of the Queen's University of Belfast constituency. It also abolished the two-member constituencies.

Under the new boundaries, Antrim was split into two single-member constituencies: North Antrim and South Antrim. Down was likewise split into North Down and South Down. Tyrone and Fermanagh was split into Fermanagh and South Tyrone in the south, and Mid Ulster in the north, which also gained further area from the Londonderry constituency.

1922–1950

Under the Government of Ireland Act 1920, Northern Ireland was created on 3 May 1921,^[4] and the number of seats at Westminister in the area it covered was reduced in number from 30 to 13, across 10 constituencies.^[21]

Under these boundaries, Antrim, Down, and Fermanagh and Tyrone each elected two MPs using the bloc voting system, and Northern Ireland had one university constituency, the Queen's University of Belfast constituency. As with other university constituencies in the UK, the QUB constituency elected 1 MP by the graduates of the university, regardless of where they resided, in addition to any other vote they might have.