Ontario's auto plants and the trade conflict

A little background

What follows covers Ontario's auto plants from February to mid-September 2026. By the end you should be able to tell which tariffs apply at the border and which are only announced. You should also see what Brampton's idled plant is waiting on. Three status words carry that. Announced means a government has said what it will do. Scheduled means a signed order sets a start date. In force means the measure applies at the border. Every light-duty vehicle plant on the federal industry department's 2024 list is in Ontario. The plants sit inside a trade conflict between Canada and the United States, widely called a trade war, that has run since early 2025. A tariff is a tax on imports, paid by the importer. Since April 3, 2025 the US has charged 25 per cent on Canadian-built cars, and on auto parts since May 3. It does so under Section 232, a US trade law that allows tariffs on national-security grounds. The North American trade agreement is called CUSMA in Canada and USMCA in the United States. A car qualifies under it when it meets the agreement's rules of origin on North American content. For a qualifying car, the importer can document its US-made parts to the US Commerce Department. Once that is approved, the 25 per cent applies only to the rest of the car's value, its non-US content. Since April 2025 Canada has charged a 25 per cent tariff on some US-built vehicles. For vehicles that qualify, it charges only on content from outside Canada and Mexico, such as US-made parts. Canada also lets automakers bring in a quota of US-built vehicles free of that tariff if they keep up production in Canada. Prime Minister Mark Carney says the US tariffs are 'unjustified'. The United States says its 2026 tariffs answer Canada's 'discrimination' against American cars, alcohol and dairy.