It’s a cliche that the 905 decides the outcomes of federal elections, but recent results back the notion.

The GTA outside Toronto went nearly entirely red for Liberal leader Justin Trudeau’s majority win in 2015; in 2011, it was blue for Stephen Harper’s.

This year, as many as 19 races in the 905 are up in the air with the election just days away, according to the website 338Canada, which projects riding-by-riding results based on available polls.

If the government is going to change on election night, you’ll see it happening in the GTA.

Here are 10 ridings to watch in the 905 Monday night:

FIND YOUR RIDING: Dig into all 338, from Yukon to St. John's South⁠—Mount Pearl and every riding in between

MEET THE CANDIDATES: Learn more about the people who want your vote

Brampton East, held by the Liberals

Brampton East is an open seat after incumbent Raj Grewal resigned from the Liberal caucus over his gambling debts. Liberal candidate Maninder Sidhu, who founded a children’s charity that works in India, is being challenged from both sides in a riding that has the largest South Asian population in the country.

Unusually for the GTA portion of the 905, the New Democrats have a legitimate chance here, and human rights lawyer Saranjit Singh should do well in an area that leader Jagmeet Singh used to represent provincially. Conservative political strategist Ramona Singh should also challenge, but likely only for second place. Public servant Teresa Burgess-Ogilvie is running for the Greens.

The riding is projected as a likely Liberal win. The party needs to retain all five Brampton seats to have a realistic chance at retaining its majority and a loss here would be a bad, bad sign for Trudeau’s chances at staying in government.

Brampton North, held by the Liberals

The Conservatives have high hopes for political strategist Arpan Khanna, who has received big-name backing from Alberta Premier Jason Kenney in his campaign to unseat one-term Liberal incumbent Ruby Sahota, the chair of the Liberals’ Ontario caucus. Both are relatively young natives of fast-growing Brampton. New Democrat community organizer Melissa Edwards worked for Jagmeet Singh in Ottawa. The Greens are running Norbert D’Costa, who is part of the provincial party leadership.

The riding is leaning Liberal, and any change here may signal the same in Brampton Centre, Brampton West and Brampton South. The city, a traditional stronghold for the federal Liberals, went blue for Harper with the 905 wave in 2011.

Burlington, held by the Liberals

Karina Gould, the incumbent minister of democratic institutions, is one of Trudeau’s most-vulnerable cabinet ministers in a bellwether riding that has followed the national result in every election since 1984.

At 32, Gould’s relative youth is somewhat at odds with Burlington’s large population of seniors. But she was younger still when she narrowly won in 2015 and, as the youngest women ever named to federal cabinet, she’s a clear rising star in the party. Gould’s running against Conservative restaurant owner Jane Michael, who previously chaired the at-times controversial Halton Catholic District School Board.

A toss up, Burlington is a measuring stick to gauge national trends. A double-digit vote share would be an excellent result for both New Democrat entrepreneur Lanaee Dupuis and Green activist Gareth Williams.

Markham-Stouffville, held by independent Jane Philpott

The SNC-Lavalin scandal has already cost the Liberals high-profile incumbent Jane Philpott — the one-time cabinet minister is running as an independent after being expelled from the party — it could also cost them this key 905 seat. Standing in the way of that outcome is star candidate Helena Jaczek, who was most recently provincial health minister under Kathleen Wynne.

In June, Jaczek said she worried the Conservatives might benefit from vote-splitting in the vast suburban riding, and that is the risk for the Liberals.

Markham-Stouffville is a projected toss up between Jaczek and Conservative entrepreneur Theodore Antony, but the polling data is sparse on Philpott’s chances. Palliative care physician Hal Berman, running for the NDP, and Green candidate Roy Long are likely to remain in the single digits.

Markham-Unionville, held by the Conservatives

Incumbent Bob Saroya won a rare Toronto-area victory for the Conservatives in 2015 when he took a seat that had been long-held by Liberal giant John McCallum before redistricting. This time around, Saroya, who’s running his fourth federal campaign, is among the more vulnerable Conservative incumbents in the 905.

The Liberals are running a strong candidate in Alan Ho, a longtime councillor in fast-growing and diverse Markham — more than half of the suburban riding’s residents were born in Asia, most of those in China, according to the most recent census.

The riding is leaning Conservative, so a loss here would be a major disappointment for Leader Andrew Scheer’s ambitions at forming the next government. Green candidate Elvin Kao, a data analyst who ran in 2015, could challenge New Democrat Gregory Hines for third.

Milton, held by the Conservatives

Is a four-time Olympic medal winner a strong enough candidate to unseat one of the brightest stars in Andrew Scheer’s Conservative party? Liberal rookie Adam van Koeverden, kayak gold medallist, twice Canada’s flag bearer, has mounted an impressive campaign to challenge Conservative deputy leader Lisa Raitt, who has been ever-present in parliament since 2008.

Milton, a family-friendly, commuter-packed riding, is a projected toss up, but, with such high profile hopefuls, the result may not match the national trend; strong candidates can swing a race on their own. Nevertheless, Raitt would be a shoe-in as a cabinet minister, so a loss for her would be deeply disappointing to the Conservatives, even if Scheer were to win in a blue wave elsewhere. (The Liberals meanwhile have high hopes for van Koeverden’s potential as a parliamentarian).

Green environmentalist Eleanor Hayward, who ran provincially last year, will be aiming for a double-digit vote share; New Democrat activist Farina Hassan will be looking for a strong third.

Loading... Loading... Loading... Loading... Loading... Loading...

Newmarket-Aurora, held by the Liberals

A battle of familiar faces in a potential bellwether riding that incumbent Kyle Peterson is not contesting. Conservative candidate Lois Brown, whose political career goes back to the Canadian Alliance days, was twice elected MP in Newmarket-Aurora in the Harper-era before losing to Peterson in 2015.

Liberal candidate Tony Van Bynen’s career in the area goes back even further than that: he was mayor of Newmarket from 2006 to last year, and regional councillor before then.

Newmarket-Aurora is projected to be a true toss up between the Liberals and Conservatives; a win for Brown might be paired with similar result in nearby King-Vaughan, also being defended by the Liberals.

New Democrat anti-poverty advocate Yvonne Kelly is not projected to challenge, but may draw votes from Van Bynen, if the NDP surges. Third would be an excellent result for Green candidate Walter Bauer, an engineer.

Mississauga-Malton, held by the Liberals

Don’t expect Navdeep Bains to lose, but do keep an eye on Mississauga-Malton; anything but a comfortable result for the incumbent minister of Innovation, Science and Economic Development would be a strong signal the Liberals are in for a very long, bad night.

And Bains, who was first elected in 2004, has been ousted in a blue wave before; he lost to controversial Conservative Eve Adams in 2011 and was out of parliament for Harper’s majority only to come back and win again (handily) in 2015.

Conservative small business owner Tom Varughese is projected to finish well behind Bains, so an upset will take a strong showing from NDP candidate Nikki Clarke, an author and longtime advocate for Malton’s Black community. A strong fourth would be a good result for Green candidate Christina Porter, a business analyst.

Mississauga-Lakeshore, held by the Liberals

A rematch between one-term MPs. Liberal incumbent Sven Spengemann comfortably returned Mississauga-Lakeshore to the Liberals in Trudeau’s 2015 wave, defeating Conservative Stella Ambler, who is one of six former Conservative MPs trying to regain their seats on Monday (The others are Ted Opitz in Etobicoke Centre, Wladyslaw Lizon in Mississauga East—Cooksville, Brown in Newmarket-Aurora, Terence Young in Oakville, and Costas Menegakis in Richmond Hill).

Before Ambler won the seat in the 2011 Harper wave, Mississauga’s waterfront riding was a solid Liberal bastion, and Spengemann is a slight favourite in the toss up projection.

A win for Ambler, who has worked as a political strategist and commentator since leaving parliament, would not be a major shock, but, in such an evenly matched race, it could be a signal of yet another wave.

NDP candidate Adam Laughton, a University of Toronto Master’s student, and Green candidate Cynthia Trentelman should battle for third.

Whitby, held by independent Celina Caesar-Chavannes

Unlike Philpott, Whitby incumbent Celina Caesar-Chavannes is not seeking re-election after she left the Liberal caucus following a clash with Trudeau amid the SNC-Lavalin scandal. But even without that risk of vote-splitting, the riding will be tough for the Liberals to retain.

Harper-era finance minister Jim Flaherty’s legacy looms large here, even five years after his death upended federal politics in the working class riding. Conservative candidate Todd McCarthy, a longtime friend and a partner at Flaherty’s old law firm, is running in part on restoring that legacy.

Liberal Ryan Turnbull, a social innovation consultant, is a newcomer who was first approached to run after giving a speech at Durham College, where he is a guest lecturer.

Another toss up, the Conservatives will have Whitby circled as a must-win if they hope to make serious gains on Monday. NDP labour activist Brian Dias and Green candidate Paul Slavchenko, an anesthesiologist, should battle for third.

Ed Tubb is an assignment editor and a contributor to the Star’s coverage of the 2019 federal election. He is based in Toronto. Follow him on Twitter: @edtubb

Read more about: