The Political RecordFederal electoral districtsNo. 35106Ontario

Thornhill

Thornhill is a federal riding in Ontario. Melissa Lantsman (Conservative, first elected to the House in 2021) represents Thornhill. Melissa Lantsman (Conservative) held Thornhill for the Conservatives in the 2025 election by 23,546 votes (35.2 points), with 66.4% of the vote. Liane Kotler (Liberal) was second with 31.2%, on a turnout of 68.9% of 98,136 electors. Member as of 2026-11-01.

Fig. 1 — Thornhill on the board, 2023 boundaries; the ridings next door as the House holds them on 2026-11-01. Open it on the board →

Who represents Thornhill

Melissa Lantsman's piece from the board. Illustration after the official portrait © House of Commons.

Melissa Lantsman

Member of Parliament for Thornhill

Conservative

MP since 2021-09-20 · 2 terms

303 speeches in the 45th Parliament, most often on Finance.

Contact and office · House of Commons →

The 2025 result: Conservative hold

Share of the valid votes by candidate, Thornhill, April 28, 2025

Shares of the 66,918 valid votes; a candidate under 1% is counted with the others. Source: Elections Canada, official voting results, the 2025 general election.

The figures

Candidate	Party	Votes	Share
Melissa Lantsman	Conservative	44,419	66.4%
Liane Kotler	Liberal	20,873	31.2%
William McCarty	New Democratic	833	1.2%
Others (2)		793	1.2%

Melissa Lantsman (Conservative) won Thornhill on April 28, 2025 with 44,419 votes, 66.4% of the 66,918 valid votes. Liane Kotler (Liberal) was second with 20,873 (31.2%), 23,546 votes and 35.2 points behind.

Of the 66,918 valid votes, Melissa Lantsman (Conservative) took 66.4%, Liane Kotler (Liberal) 31.2% and William McCarty (New Democratic) 1.2%; the 2 other candidates took 1.2% together. Turnout was 68.9% of 98,136 electors: 67,581 ballots cast, 66,918 of them valid, for 5 candidates.

Since 2021

Against the 2021 result on these boundaries, the Conservatives are up 15.1 (51.3% to 66.4%), the Liberals down 4.6 (35.8% to 31.2%) and the New Democrats down 4.7 (5.9% to 1.2%), in points of the valid votes.

2021 is Elections Canada's transposition of that election onto the 2023 boundaries, not an election held on these lines.

Since 2004: no party has held it

The party first in Thornhill at each general election, 2004 to 2025, on today's boundaries

2004Liberal55.1%by 21.4 points over the Conservatives
2006Liberal53.5%by 20.4 points over the Conservatives
2008changed handsConservative48.0%by 7.9 points over the Liberals
2011Conservative61.0%by 36.8 points over the Liberals
2015Conservative57.6%by 22.9 points over the Liberals
2019Conservative53.8%by 17.8 points over the Liberals
2021Conservative51.3%by 15.5 points over the Liberals
2025Conservative66.4%by 35.2 points over the Liberals

Each election carried onto today's boundaries by where the riding's 2025 electors lived: our estimate to 2019, Elections Canada's transposition for 2021, the official result for 2025. Parties are counted as they ran.

The figures

Year	First	Share	Second	Margin (pts)	Basis
2004	Liberal	55.1%	Conservative	21.4	carried, our estimate
2006	Liberal	53.5%	Conservative	20.4	carried, our estimate
2008	Conservative	48.0%	Liberal	7.9	carried, our estimate
2011	Conservative	61.0%	Liberal	36.8	carried, our estimate
2015	Conservative	57.6%	Liberal	22.9	carried, our estimate
2019	Conservative	53.8%	Liberal	17.8	carried, our estimate
2021	Conservative	51.3%	Liberal	15.5	transposed by Elections Canada
2025	Conservative	66.4%	Liberal	35.2	official result

The Conservatives were first at six of the eight general elections from 2004 to 2025, the Liberals at two; it changed hands once. In 2025 the Conservatives took 66.4% of the vote here, 18.0 points above their average of 48.4% at the seven general elections from 2004 to 2021.

On today's boundaries the Liberals were first here in 2004 (55.1%) and 2006 (53.5%) and the Conservatives in 2008 (48.0%), 2011 (61.0%), 2015 (57.6%), 2019 (53.8%), 2021 (51.3%) and 2025 (66.4%), each with the share of the valid votes shown.

A stronghold is a party first at every general election since 2004, by an average of 20 points or more over the next party; held, first at every one; usually, first at all but one. By-elections are not counted. By this rule 160 of the 343 ridings have no degree. The results before 2021 are carried onto today's boundaries by where the riding's 2025 electors lived: our estimate, from the older boundaries of Taylor, Lucas, Kirby and Hewitt and the results in Sevi's "Who Runs?". 2021 is Elections Canada's transposition, and 2025 the official result.

Before 2025

2021 Conservative · Melissa Lantsman, by 7,519 votes (15.0 pts)
2019 Conservative · Peter Kent, by 10,241 votes (19.2 pts)
2015 Conservative · Peter Kent, by 13,516 votes (24.8 pts)

In the old Thornhill on the 2013 boundaries, the riding most of the 2025 electors in today's Thornhill lived in; Elections Canada's official results.

What kind of place Thornhill is

Population: 124,8702021 census
Area: 70km²
Density: 1,779people per km²
Electors: 98,136on the 2025 lists

Distinctions · ranked against all 343 ridings

6th-smallest Indigenous share
0.2% report an Indigenous identity, 6th lowest of 343 (Share with an Indigenous identity, 2021 census)

Share aged 25-64 with a bachelor's degree or higher is 57.4% — about 2.0 times the median riding's 28.2%.
highestlowest19th highest of 343
Share who are immigrants is 52.1% — about 3.0 times the median riding's 17.3%.
highestlowest25th highest of 343
Median total household income is $106,000 — about 1.3 times the median riding's $84,000.
highestlowest44th highest of 343
Share with French as a mother tongue is 0.8% — about 50 percent of the median riding's 1.6%.
highestlowest61st lowest of 343
Share of households that own their home is 78.4% — a little higher than the median riding's 71.4%.
highestlowest75th highest of 343
Median age is 43.2 — a little higher than the median riding's 41.6.
highestlowest118th highest of 343

2021 Census on the 2023 boundaries; each rule places this riding among all 343. Density is the census population over the riding's area.

IDid this riding change?

Yes. 93% of the 2025 electors in today's Thornhill lived in the old Thornhill; by area, 6% of the riding came from other ridings.

Share of today's electorsFormer riding

93.3%Thornhill 93.6% of the area

6.7%King—Vaughan 6.3% of the area · 1% of it kept

0.0%Richmond Hill 0.1% of the area · 0.2% of it kept

How this is measured. Electors: the share of the current riding's 2025 ordinary-list electors who lived in each former riding, each 2025 polling division placed in the 2013 riding a point inside it falls in. Area: the share of the current riding's area that came from each former riding, by intersecting the 2013 and 2023 boundary files, and how much of the former riding that part was. Area is land, not population. Elections Canada counts 48 of 343 ridings as entirely unchanged.

IIThe 2025 result

Candidate	Party	Votes	%	2021	±
Melissa Lantsman	Conservative	44,419	66.4%	51.3%	+15.1
Liane Kotler	Liberal	20,873	31.2%	35.8%	−4.6
William McCarty	New Democratic	833	1.2%	5.9%	−4.7

2 further candidates, each under 1% of the vote

Amir Hart	People's	440	0.7%
Dominic Piotrowski	Green	353	0.5%

The 2021 column is Elections Canada's official transposition of the 2021 result onto these 2023 boundaries. ± is the change in each party's share. It is not "swing": with four or more competitive parties there is no single pair to swing between.

IIIHow close was it, really

Third place vs. the margin

833 votes

New Democratic took fewer than the 23,546-vote margin.

Election-day polls won by others

21 of 240

No poll ended in a tie.

Fig. 2 — Each square is one election-day poll: ■ won by the Conservatives (219) · ■ won by another party (21).

Flip the seatHypothetical

It would have taken 11,774 voters switching from Conservative to Liberal — 17.6% of the 66,918 valid votes, 17.6 points — to change the result. No ballot was cast this way; this only moves votes between the top two.

Voters who switch: 0023,548

Conservative44,419

Liberal20,873

Still Conservative by 23,546 votes. Actual margin: 23,546.

IVElection day versus advance

Only 54.8% of this riding's votes were cast at election-day polls. The rest were advance or special ballots.

On election day the Conservatives took 64.1%, the Liberals 32.8% and the New Democrats 1.6%; in advance and special ballots, 69.1%, 29.2% and 0.8%, in that order.

Share of the valid votes by party, election-day polls against advance and special ballots, Thornhill, April 28, 2025

Shares of the valid votes cast at election-day polls, and of those cast at advance polls, at mobile polls and by special ballot; the gap is the second less the first, in points. Source: Elections Canada, poll-by-poll results, the 2025 general election.

The figures

Party	Election day	Advance and special	Gap
Conservative	64.1%	69.1%	+5.0
Liberal	32.8%	29.2%	−3.6
New Democratic	1.6%	0.8%	−0.8

An association, not a cause. Voters who cast ballots before election day differed from those who turned out on the day. It does not say why. There is no poll-level turnout figure on this page: the elector count on a polling division includes people who voted in advance and were counted elsewhere.

VWhere it is

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Fig. 3 — Thornhill and its 7 neighbouring ridings.

Sources and citation

"Thornhill — federal riding profile and 2025 results."
The Political Record. https://politicalrecord.ca/riding/thornhill/
Accessed 2026-11-10.

Results and transposition: Elections Canada. Boundaries: Elections Canada / Statistics Canada, Open Government Licence – Canada. Census: Statistics Canada 2021 Census. Member: House of Commons.

Figures reconcile to the certified national total of 19,641,663 votes. The member is as the House of Commons listed them on 2026-11-01. Page built 2026-11-10.