The measures targeting Can$16.6 billion (US$12.6 billion) in US steel, aluminum and consumer goods will take effect on Sunday when Canadians across the country will be celebrating a national holiday and just days before Americans celebrate their independence.
The tit-for-tat duties follow punishing US steel and aluminum tariffs imposed at the start of June. Ottawa also unveiled Can$2 billion (US$1.5 billion) in aid for the two sectors.
"Canada has no choice but to retaliate with a measured reciprocal dollar-for-dollar response. That is what we are doing," said Foreign Minister Chrystia Freeland, making the announcement at a steel facility in Hamilton, Ontario where she was flanked by brawny workers in yellow hardhats.
"We will not escalate and we will not back down," she added while noting that this trade action was the strongest taken by Ottawa since World War II and urging the Trump administration to rescind its own tariffs.
The list of more than 250 goods subject to Canadian duties -- including Florida juice, Wisconsin toilet paper or North Carolina gherkins, which are labor intensive to produce -- aim to pressure Trump supporters in November's US midterm elections.
They will add 25 percent to the cost of imported US steel and 10 percent to aluminum imports and consumer goods.
Canada and Mexico were initially exempted from the US steel and aluminum tariffs but Trump ended this in June amid stalled talks to revamp a 1994 trilateral trade deal.
Businesspeople warned Canadian lawmakers this week that an escalation into an all-out trade war would be devastating to the Canadian economy, which sends about 75 percent of its exports to the United States.
If Trump steps up his attacks on Canada's economy and imposes a tariff on automobiles as threatened, it would lead to "carmageddon," Flavio Volpe, president of the Automotive Parts Manufacturers Association, told a Commons committee hearing on Tuesday.
Meanwhile, Canadians are overwhelmingly in favor of today's retaliatory tariffs.
In Ottawa, officials and others have declined an invitation to the US ambassador's annual July 4th party.
"I've politely declined because I'm not happy with the direction of the American government and their constant attacks on our country," Ottawa Mayor Jim Watson told public broadcaster CBC.
Canadian patriotism, meanwhile, has bristled under hashtags like #BoycottUSA, #BuyCanadian and #VacationCanada that urge people not to buy American goods and travel packages.