# 2026 Terrebonne federal by-election
The 2026 Terrebonne federal by-election was a House of Commons by-election held on Monday, April 13, 2026, in the Quebec riding (Canadian term for a federal electoral district) of Terrebonne, after the [Supreme Court of Canada](https://www.edgepedia.org/supreme-court-of-canada) annulled the riding's one-vote Liberal result from the 2025 general election. Liberal candidate [Tatiana Auguste](https://www.edgepedia.org/tatiana-auguste), whose 2025 victory had been voided, won the by-election with 48.3% of the vote, holding the seat for the Liberals against [Bloc Québécois](https://www.edgepedia.org/bloc-quebecois) candidate Nathalie Sinclair-Desgagné by 668 votes.[1](https://politicalrecord.ca/riding/terrebonne/) The vote was held alongside by-elections in Scarborough Southwest and University—Rosedale in Ontario.[2](https://www.elections.ca/content.aspx?dir=2026%2Fspr&document=guige24073&lang=e§ion=ele)
| Key fact | Detail |
|---|---|
| Date | Monday, April 13, 2026; advance polls April 3–6, 2026[2](https://www.elections.ca/content.aspx?dir=2026%2Fspr&document=guige24073&lang=e§ion=ele) |
| Trigger | Supreme Court of Canada annulled the 2025 general election result in Terrebonne on February 13, 2026[3](https://www.elections.ca/content.aspx?dir=pre&document=feb1326&lang=e§ion=med) |
| Winner | Tatiana Auguste (Liberal), 22,445 votes, 48.3%[1](https://politicalrecord.ca/riding/terrebonne/) |
| Runner-up | Nathalie Sinclair-Desgagné (Bloc Québécois), 21,777 votes, 46.9%[1](https://politicalrecord.ca/riding/terrebonne/) |
| Margin | 668 votes (1.4 points) of 46,443 valid votes[1](https://politicalrecord.ca/riding/terrebonne/) |
| Turnout | 51.1% of 91,534 electors; 371 rejected ballots[1](https://politicalrecord.ca/riding/terrebonne/) |
| Ballot | Adapted write-in ballot on which electors wrote in the candidate's name; 48 candidates on the ballot[4](https://www.elections.ca/content.aspx?dir=2026%2F24073&document=faq&lang=e§ion=ele) • [1](https://politicalrecord.ca/riding/terrebonne/) |
## Background: the annulled 2025 result
In the general election of April 28, 2025, preliminary results had shown Liberal candidate Tatiana Auguste leading in Terrebonne, and a judicial recount confirmed her as the winner over Bloc Québécois candidate Nathalie Sinclair-Desgagné by a single vote, with Auguste taking 38.7% of the vote.[5](https://publications.gc.ca/collections/collection_2025/elections/SE1-1-1-2025-eng.pdf) • [1](https://politicalrecord.ca/riding/terrebonne/) The Bloc candidate challenged the result after a supporter complained that she had tried to vote by mail using a special ballot that was not counted because of an error on Elections Canada's part.[6](https://apnews.com/article/1b165c66e00a9f76b0072b815a458d5f) Elections Canada received 59 submissions as of May 16, 2025 regarding the recount efforts.[7](https://www.elections.ca/abo/comp/apr2825/ceoapp_e.pdf)
On Friday, February 13, 2026, the Supreme Court of Canada granted the appeal in the contested election and annulled the election result, and Elections Canada announced it was ready to administer a by-election.[3](https://www.elections.ca/content.aspx?dir=pre&document=feb1326&lang=e§ion=med) The riding therefore had no sitting member of Parliament from that date.[8](https://www.pollingforecast.com/ca/seats/24073)
## Calling and administering the by-election
The Speaker of the House of Commons addressed a warrant for the issue of a writ to the Chief Electoral Officer, Stéphane Perrault, on Monday, February 16, 2026, the earliest date the by-election could be held being Monday, April 6, 2026.[9](https://elections.ca/content.aspx/content.aspx?dir=cir%2Fdis&document=vacant_2025&lang=e§ion=res) • [10](https://www.elections.ca/content.aspx?dir=pre&document=feb1626&lang=e§ion=med) The Speaker informed the House of the vacancy on February 23, 2026, under subsection 28(1) of the Parliament of Canada Act.[11](https://www.ourcommons.ca/Content/House/451/Journals/087/Journal087.PDF)
**The stakes for the government.** On March 8, 2026, Prime Minister Mark Carney called the by-elections in Terrebonne, Scarborough Southwest, and University—Rosedale. The Liberals held 169 of the House of Commons' seats and needed 172 for a majority government; Scarborough Southwest and University—Rosedale were considered safe Liberal seats, while Terrebonne was considered a toss-up. If the Liberals won all three, Commons Speaker Francis Scarpaleggia would still have needed to cast tiebreaking votes to pass government legislation.[6](https://apnews.com/article/1b165c66e00a9f76b0072b815a458d5f) The writ for Terrebonne was issued on March 8, 2026, with polling day set for April 13.[12](https://www.elections.ca/content.aspx?dir=loi%2Fadap%2Fada4&document=byel17&lang=e§ion=res)
**An unusually long ballot.** Because the by-election drew 48 candidates, Elections Canada used an adapted ballot, similar to a special ballot, on which electors wrote in the name of the candidate they were voting for rather than marking an X beside a printed name.[1](https://politicalrecord.ca/riding/terrebonne/) • [4](https://www.elections.ca/content.aspx?dir=2026%2F24073&document=faq&lang=e§ion=ele) Elections Canada published guidance explaining that a vote for only a party name, without the candidate's name, would not count, and addressed questions about misspelled names and ballot security features.[4](https://www.elections.ca/content.aspx?dir=2026%2F24073&document=faq&lang=e§ion=ele) The Chief Electoral Officer also issued adaptations under subsection 17(1) of the Canada Elections Act to modify the ballot and make consequential amendments for this by-election.[13](https://www.elections.ca/content.aspx?dir=loi%2Fadap%2Fada%2Fmar3126&document=adapt1&lang=e§ion=res)
## Result
Auguste held Terrebonne for the Liberals with 22,445 votes and 48.3% of the vote; Sinclair-Desgagné took 21,777 votes and 46.9%. The margin was 668 votes, 1.4 points, out of 46,443 valid votes, and turnout was 51.1% of 91,534 electors, with 371 rejected ballots.[1](https://politicalrecord.ca/riding/terrebonne/) The by-election figures were validated by the returning officer.[14](https://ridingwatch.ca/ridings/terrebonne.html)
The result marked a substantial shift from the 2025 general election, when both the Liberals and the Bloc had taken 38.7% of the vote. The Liberal share rose by 9.6 points, while the Conservatives, who had taken 18.2% in 2025 under Adrienne Charles, fell to 3.3% in the by-election; the NDP's Maxime Beaudoin fell from 2.6% to 0.5%.[1](https://politicalrecord.ca/riding/terrebonne/) • [14](https://ridingwatch.ca/ridings/terrebonne.html) The Green Party's Benjamin Rankin and the People's Party's Maria Cantore, who had received 1.0% and 0.7% respectively in 2025, ran again and were defeated.[1](https://politicalrecord.ca/riding/terrebonne/) • [15](https://www.ourcommons.ca/Members/en/election-candidates?%3FelectionEventId=7788507&constituencyName=&lastname=C&nameFirstLetter=C)
The seat had been vacant from February 13, 2026, when the 2025 result was annulled, until Auguste's by-election victory returned it to the Liberals.[3](https://www.elections.ca/content.aspx?dir=pre&document=feb1326&lang=e§ion=med) • [8](https://www.pollingforecast.com/ca/seats/24073)
## References
1. [Terrebonne — federal riding profile and 2025 results, The Political Record](https://politicalrecord.ca/riding/terrebonne/)
2. [Guide to the federal by-election in Terrebonne – April 13, 2026, Elections Canada](https://www.elections.ca/content.aspx?dir=2026%2Fspr&document=guige24073&lang=e§ion=ele)
3. [Result of the 45th General Election in Terrebonne Annulled, Elections Canada](https://www.elections.ca/content.aspx?dir=pre&document=feb1326&lang=e§ion=med)
4. [FAQs – By-election in Terrebonne (QC), Elections Canada](https://www.elections.ca/content.aspx?dir=2026%2F24073&document=faq&lang=e§ion=ele)
5. [Report of the Chief Electoral Officer on the 45th General Election of April 28, 2025, Elections Canada / Publications Canada](https://publications.gc.ca/collections/collection_2025/elections/SE1-1-1-2025-eng.pdf)
6. [Carney calls special elections for three Canadian districts, which could lead to majority government, AP News (March 8, 2026)](https://apnews.com/article/1b165c66e00a9f76b0072b815a458d5f)
7. [Appearance of the Chief Electoral Officer on the Report on the 45th General Election of April 28, 2025, Elections Canada](https://www.elections.ca/abo/comp/apr2825/ceoapp_e.pdf)
8. [Terrebonne: projection and results, Polling Forecast](https://www.pollingforecast.com/ca/seats/24073)
9. [Vacant Seats in the House of Commons Since the 2025 General Election, Elections Canada](https://elections.ca/content.aspx/content.aspx?dir=cir%2Fdis&document=vacant_2025&lang=e§ion=res)
10. [A Federal Seat Is Vacant in Terrebonne, Elections Canada (February 16, 2026)](https://www.elections.ca/content.aspx?dir=pre&document=feb1626&lang=e§ion=med)
11. [Journals No. 087, Monday, February 23, 2026, 45th Parliament, 1st Session, House of Commons of Canada](https://www.ourcommons.ca/Content/House/451/Journals/087/Journal087.PDF)
12. [Administration of the voting procedure provided by section 241 of the Special Voting Rules as Adapted for the Purposes of a By-election, Elections Canada](https://www.elections.ca/content.aspx?dir=loi%2Fadap%2Fada4&document=byel17&lang=e§ion=res)
13. [17-B-2026-01 – Adaptations to modify the ballot and to make consequential amendments, Elections Canada](https://www.elections.ca/content.aspx?dir=loi%2Fadap%2Fada%2Fmar3126&document=adapt1&lang=e§ion=res)
14. [Terrebonne — Election Outlook & Projection, RidingWatch](https://ridingwatch.ca/ridings/terrebonne.html)
15. [Election Candidates – By-election, Monday, April 13, 2026, House of Commons of Canada](https://www.ourcommons.ca/Members/en/election-candidates?%3FelectionEventId=7788507&constituencyName=&lastname=C&nameFirstLetter=C)
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*Topic: Encyclopedia › Society and history › Politics and government › Elections and representation › Elections and referendums › National and subnational elections outside the US and UK › Canadian election events*
*Initially written Sep 17, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license