Government of Ireland Act 1920 (constituencies)

The Government of Ireland Act 1920 (10 & 11 Geo. 5 c. 67) was an Act passed by the Parliament of the United Kingdom to create two separate parliaments in Ireland: the Parliament of Northern Ireland and the Parliament of Southern Ireland. The Fifth Schedule to this act provided the constituencies for the House of Commons in these two separate parliaments. These same constituencies also replaced those provided in the Redistribution of Seats (Ireland) Act 1918 for representation of Ireland in the House of Commons of the United Kingdom at Westminster. Sinn Féin used these constituencies to elect the Second Dáil (1921–22) and those constituencies in Southern Ireland were used to elect the Third Dáil (1922–23).

Operation of constituencies
The First Dáil had used the constituencies which elected MPs to the House of Commons at the 1918 general election. In May 1921, Dáil Éireann resolved to use the constituencies in the Government of Ireland Act 1920 (in both parts of Ireland). The 1921 elections were used to elect the Second Dáil. This increased the total number of seats in the Dáil from 105 in 1918 to 180 in 1921 (52 in Northern Ireland and 128 in Southern Ireland, subsequently the Irish Free State). Only representatives from Sinn Féin sat in the Dáil. In practice this was confined to 125 TDs representing 130 seats.

Only the Dublin University MPs attended for the intended first meeting of the House of Commons of Southern Ireland, with those elected for Sinn Féin sitting as TDs in Dáil Éireann.

The members elected for Southern Ireland assembled in January to give legal effect to the Anglo-Irish Treaty under the terms of the British government, which had not recognised the Anglo-Irish Treaty Dáil vote. This included the Pro-Treaty Sinn Féin TDs and the four representatives of Dublin University. The 1922 Irish general election was held on the constituencies under this Act.

Under the terms of the Treaty, the Irish Free State left the United Kingdom on 6 December 1922. Therefore, only constituencies in Northern Ireland returned MPs at the 1922 United Kingdom general election held on 15 November, and the Westminster constituencies designated for Southern Ireland were never used.

The 1923 general election was the first election in the Irish Free State, and was contested under the new constituencies in the Electoral Act 1923.

In the House of Commons of Northern Ireland, the constituencies were replaced under the House of Commons (Method of Voting and Redistribution of Seats) Act (Northern Ireland) 1929 with single-seat constituencies elected by first-past-the-post voting. Queen's University of Belfast remained as a four-seat constituency until its abolition in 1969.

The United Kingdom House of Commons constituencies in Northern Ireland were altered by the Representation of the People Act 1948, including the abolition of the Queen's University of Belfast constituency. This took effect at the 1950 general election.

Comparison with 1918 constituencies
Constituencies in the Government of Ireland Act 1920 were defined by reference to one or more constituencies as defined in the Redistribution of Seats (Ireland) Act 1918.

Northern Ireland
{| class="wikitable"
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Belfast
''1918 Act: 9 MPs 1920 Act: 16 MPs in NIHC & 4 MPs in UKHC'' !1918 Act!!1920 Act
 * Belfast, Pottinger Division (one MP)
 * rowspan=2| Belfast East (four MPs)
 * Belfast, Victoria Division (one MP)
 * Belfast, Duncairn Division (one MP)
 * rowspan=2| Belfast North (four MPs)
 * Belfast, Shankill Division (one MP)
 * Belfast, Cromac Division (one MP)
 * rowspan=2| Belfast South (four MPs)
 * Belfast, Ormeau Division (one MP)
 * Belfast, Falls Division (one MP)
 * rowspan=3| Belfast West (four MPs)
 * Belfast, St Anne's Division (one MP)
 * Belfast, Woodvale Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Belfast, Ormeau Division (one MP)
 * Belfast, Falls Division (one MP)
 * rowspan=3| Belfast West (four MPs)
 * Belfast, St Anne's Division (one MP)
 * Belfast, Woodvale Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Belfast, Woodvale Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Antrim
''1918 Act: 4 MPs 1920 Act: 7 MPs in NIHC & 2 MPs in UKHC'' !1918 Act!!1920 Act
 * Antrim, East Division (one MP)
 * rowspan=4| Antrim (seven MPs)
 * Antrim, Mid Division (one MP)
 * Antrim, North Division (one MP)
 * Antrim, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Antrim, North Division (one MP)
 * Antrim, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Armagh
''1918 Act: 3 MPs 1920 Act: 4 MPs in NIHC & 1 MP in UKHC'' !1918 Act!!1920 Act
 * Armagh, Mid Division (one MP)
 * rowspan=3| Armagh (four MPs)
 * Armagh, North Division (one MP)
 * Armagh, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Armagh, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Down
''1918 Act: 5 MPs 1920 Act: 8 MPs in NIHC & 2 MPs in UKHC'' !1918 Act!!1920 Act
 * Down, East Division (one MP)
 * rowspan=5| Down (eight MPs)
 * Down, Mid Division (one MP)
 * Down, North Division (one MP)
 * Down, South Division (one MP)
 * Down, West Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Down, South Division (one MP)
 * Down, West Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Down, West Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Fermanagh and Tyrone
''1918 Act: 5 MPs 1920 Act: 8 MPs in NIHC & 2 MPs in UKHC'' !1918 Act!!1920 Act
 * Fermanagh, North Division (one MP)
 * rowspan=5| Fermanagh and Tyrone (eight MPs)
 * Fermanagh, South Division (one MP)
 * Tyrone, North East Division (one MP)
 * Tyrone, North West Division (one MP)
 * Tyrone, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Tyrone, North West Division (one MP)
 * Tyrone, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Tyrone, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Londonderry
''1918 Act: 3 MPs 1920 Act: 5 MPs in NIHC & 1 MP in UKHC'' !1918 Act!!1920 Act
 * Londonderry City (one MP)
 * rowspan=3| Londonderry (five MPs)
 * Londonderry, North Division (one MP)
 * Londonderry, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Londonderry, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Universities
''1918 Act: 1 MPs 1920 Act: 4 MPs in NIHC & 1 MP in UKHC'' !1918 Act!!1920 Act
 * Queen's University of Belfast (one MP)
 * Queen's University of Belfast (four MPs)
 * }
 * }

Southern Ireland
{| class="wikitable"
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Ulster (part)
Representation increased from 8 to 12 MPs !1918 Act!!1920 Act
 * Cavan, East Division (one MP)
 * rowspan=2| Cavan (three MPs)
 * Cavan, West Division (one MP)
 * Donegal, East Division (one MP)
 * rowspan=4| Donegal (six MPs)
 * Donegal, North Division (one MP)
 * Donegal, South Division (one MP)
 * Donegal, West Division (one MP)
 * Monaghan, North Division (one MP)
 * rowspan=2| Monaghan (three MPs)
 * Monaghan, North Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Donegal, West Division (one MP)
 * Monaghan, North Division (one MP)
 * rowspan=2| Monaghan (three MPs)
 * Monaghan, North Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Monaghan, North Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Leinster
Representation increased from 27 to 44 MPs !1918 Act!!1920 Act
 * Dublin, College Green Division (one MP)
 * rowspan=2| Mid Dublin (four MPs)
 * Dublin, Dublin Harbour Division (one MP)
 * Dublin, Clontarf Division (one MP)
 * rowspan=3| North West Dublin (four MPs)
 * Dublin, St James's Division (one MP)
 * Dublin, St Michan's Division (one MP)
 * Dublin, St Patrick's Division (one MP)
 * rowspan=2| Dublin South (four MPs)
 * Dublin St Stephen's Green Division (one MP)
 * County Dublin, North Division (one MP)
 * rowspan=4| Dublin County (six MPs)
 * County Dublin, Pembroke Division (one MP)
 * County Dublin, Rathmines Division (one MP)
 * County Dublin, South Division (one MP)
 * King's County (one MP)
 * rowspan=2| King's County-Queen's County (four MPs)
 * Queen's County (one MP)
 * Kildare, North Division (one MP)
 * rowspan=4| Kildare–Wicklow (five MPs)
 * Kildare, South Division (one MP)
 * Wicklow, East Division (one MP)
 * Wicklow, West Division (one MP)
 * Wexford, North Division (one MP)
 * rowspan=2| Wexford (four MPs)
 * Wexford, South Division (one MP)
 * County Carlow (one MP)
 * rowspan=3| Carlow–Kilkenny (four MPs)
 * Kilkenny, North Division (one MP)
 * Kilkenny, South Division (one MP)
 * Longford County (one MP)
 * rowspan=2| Longford–Westmeath (four MPs)
 * Westmeath County Division (one MP)
 * Louth County (one MP)
 * rowspan=3| Louth–Meath (five MPs)
 * Meath, North Division (one MP)
 * Meath, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Wicklow, West Division (one MP)
 * Wexford, North Division (one MP)
 * rowspan=2| Wexford (four MPs)
 * Wexford, South Division (one MP)
 * County Carlow (one MP)
 * rowspan=3| Carlow–Kilkenny (four MPs)
 * Kilkenny, North Division (one MP)
 * Kilkenny, South Division (one MP)
 * Longford County (one MP)
 * rowspan=2| Longford–Westmeath (four MPs)
 * Westmeath County Division (one MP)
 * Louth County (one MP)
 * rowspan=3| Louth–Meath (five MPs)
 * Meath, North Division (one MP)
 * Meath, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * rowspan=2| Longford–Westmeath (four MPs)
 * Westmeath County Division (one MP)
 * Louth County (one MP)
 * rowspan=3| Louth–Meath (five MPs)
 * Meath, North Division (one MP)
 * Meath, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Meath, North Division (one MP)
 * Meath, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Munster
Representation increased from 24 to 40 MPs !1918 Act!!1920 Act
 * Cork City (two MPs)
 * Cork City (four MPs)
 * Clare, East Division (one MP)
 * rowspan=2| Clare (four MPs)
 * Clare, West Division (one MP)
 * Limerick City (one MP)
 * rowspan=2| Limerick City–Limerick East (four MPs)
 * Limerick, East Division (one MP)
 * Kerry, East Division (one MP)
 * rowspan=5| Kerry–Limerick West (eight MPs)
 * Kerry, North Division (one MP)
 * Kerry, South Division (one MP)
 * Kerry, West Division (one MP)
 * Limerick, West Division (one MP)
 * Cork, East Division (one MP)
 * rowspan=2| Cork East and North East (three MPs)
 * Cork, North East Division (one MP)
 * Cork, Mid Division (one MP)
 * rowspan=5| Cork Mid, North, South, South East and West (eight MPs)
 * Cork, North Division (one MP)
 * Cork, South Division (one MP)
 * Cork, South East Division (one MP)
 * Cork, West Division (one MP)
 * Tipperary, East Division (one MP)
 * rowspan=3| Waterford–Tipperary East (five MPs)
 * Waterford City (one MP)
 * County Waterford (one MP)
 * Tipperary, Mid Division (one MP)
 * rowspan=3| Tipperary Mid, North and South (four MPs)
 * Tipperary, North Division (one MP)
 * Tipperary, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Cork, North Division (one MP)
 * Cork, South Division (one MP)
 * Cork, South East Division (one MP)
 * Cork, West Division (one MP)
 * Tipperary, East Division (one MP)
 * rowspan=3| Waterford–Tipperary East (five MPs)
 * Waterford City (one MP)
 * County Waterford (one MP)
 * Tipperary, Mid Division (one MP)
 * rowspan=3| Tipperary Mid, North and South (four MPs)
 * Tipperary, North Division (one MP)
 * Tipperary, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * County Waterford (one MP)
 * Tipperary, Mid Division (one MP)
 * rowspan=3| Tipperary Mid, North and South (four MPs)
 * Tipperary, North Division (one MP)
 * Tipperary, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Tipperary, North Division (one MP)
 * Tipperary, South Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Connacht
Representation increased from 13 to 24 MPs !1918 Act!!1920 Act
 * Galway, Connemara Division (one MP)
 * rowspan=4| Galway (seven MPs)
 * Galway, East Division (one MP)
 * Galway, North Division (one MP)
 * Galway, South Division (one MP)
 * Mayo, North Division (one MP)
 * rowspan=2| Mayo North and West (four MPs)
 * Mayo, West Division (one MP)
 * Mayo, South Division (one MP)
 * rowspan=2| Mayo South–Roscommon South (four MPs)
 * Roscommon, South Division (one MP)
 * Mayo, East Division (one MP)
 * rowspan=3| Sligo–Mayo East (five MPs)
 * Sligo, North Division (one MP)
 * Sligo, South Division (one MP)
 * Leitrim County (one MP)
 * rowspan=2| Leitrim–Roscommon North (four MPs)
 * Roscommon, North Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Mayo, East Division (one MP)
 * rowspan=3| Sligo–Mayo East (five MPs)
 * Sligo, North Division (one MP)
 * Sligo, South Division (one MP)
 * Leitrim County (one MP)
 * rowspan=2| Leitrim–Roscommon North (four MPs)
 * Roscommon, North Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * Leitrim County (one MP)
 * rowspan=2| Leitrim–Roscommon North (four MPs)
 * Roscommon, North Division (one MP)
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |
 * colspan="2" bgcolor="ccccff" |

Universities
Representation increased from 3 to 8 MPs !1918 Act!!1920 Act
 * Dublin University (two MPs)
 * Dublin University (four MPs)
 * National University (one MP)
 * National University (four MPs)
 * }
 * National University (four MPs)
 * }