Notional results for a UK general election on 12 December 2019 Northern Ireland - Elections won by Sinn Féin
A notional general election to the 58th Parliament of the United Kingdom with an electorate of 47,558,398, having 32,014,119 valid votes.
| Constituency | Electorate | Turnout | Votes | Vote share | Majority |
| Belfast North | 71,372 | 67.4% | 23,158 | 48.1% | 3,739 |
| Belfast West | 71,921 | 59.6% | 20,786 | 48.5% | 12,997 |
| Fermanagh and South Tyrone | 74,643 | 69.2% | 21,968 | 42.5% | 510 |
| Mid Ulster | 70,094 | 63.5% | 20,372 | 45.7% | 9,806 |
| Newry and Armagh | 74,585 | 62.4% | 19,088 | 41.0% | 9,673 |
| South Down | 71,772 | 62.7% | 13,863 | 30.8% | 1,623 |
| West Tyrone | 70,614 | 62.2% | 17,604 | 40.1% | 8,074 |
Turnout as calculated by the House of Commons Library, is the total number of votes cast and not spoiled, divided by the size of the electorate.
Estimates of the 2019 general election result in new constituencies
BBC News, ITV News, Sky News and the Press Association have together produced estimates of the 2019 general election result as if the new constituencies recommended by the separate Parliamentary Boundary Commissions for England, Scotland, Wales and Northern Ireland had then been in existence.
Rallings & Thrasher, Professor David Denver (Scotland), Nicholas Whyte (NI) for Sky News, PA, BBC News and ITV News.
An explanation of the methods used and the electoral impact of the changes can be found in the linked document.