As President Trump imposes tariffs on products from countries around the world, foreign governments are answering back with tariffs of their own.

China has targeted corn farmers and carmakers. Canada has put tariffs on poultry plants and air-conditioning manufacturers, while Europe will hit American steel mills and slaughter houses.

Since Mr. Trump ordered steep levies on some of America’s largest trading partners in February and March, other countries have begun imposing their own tariffs on American exports in an attempt to put pressure on the president to relent.

The retaliatory tariffs have been carefully designed to hit Mr. Trump where it hurts: Nearly 8 million Americans work in industries targeted by the levies and the majority are Trump voters, a New York Times analysis shows.

The figures underscore the dramatic impact that a trade war could have on American workers, potentially causing Mr. Trump’s economic strategy to backfire. Mr. Trump has argued that tariffs will help boost American jobs. But economists say that retaliatory tariffs can cancel out that effect.

The countermeasures are aimed at industries that employ roughly 7.75 million people across the United States. The bulk of those — 4.48 million — are in counties that voted for Mr. Trump in the last election, compared with 3.26 million jobs in counties that voted for former Vice President Kamala Harris, according to a calculation by The Times that included examining retaliatory tariffs on more than 4,000 product categories.

These totals are the number of jobs in industries that foreign countries have targeted with their tariffs — not the number of jobs that will actually be lost because of tariffs, which is likely to be significantly lower. But industries hit by retaliatory tariffs are likely to sell fewer goods on foreign markets, which may mean lower profits and job losses.

The jobs that could be hit by retaliation are especially concentrated in pockets of the upper Midwest, South and Southeast, including many rural parts of the country that are responsible for producing agricultural goods. It also includes areas that produce coal, oil, car parts and other manufactured products.

Robert Maxim, a fellow at the Brookings Metro, a Washington think tank that has done similar analysis, said that other countries had particularly targeted Trump-supporting regions and places where “Trump would like to fashion himself as revitalizing the U.S.” That includes smaller manufacturing communities in states like Wisconsin, Indiana and Michigan, as well as southern states like Kentucky and Georgia, he said.

The message foreign countries are trying to send, he said, is, “You think you can bully us, well, we can hurt you too. And by the way, we know where it really matters.”

Retaliation may also mean concentrated pain for some industries, like farming. In Mr. Trump’s first term, American farmers – a strong voting bloc for the president – were targeted by China and other governments, which caused U.S. exports of soybeans and other crops to plummet.

Chinese buyers shifted to purchasing more agricultural goods from nations like Argentina and Brazil instead, and U.S. farmers had a difficult time winning back those contracts in subsequent years. Mr. Trump tried to offset those losses by giving farmers more than $20 billion in payments to compensate for the pain of the trade war.

One analysis published last year by economists at M.I.T., the World Bank and elsewhere found that retaliatory tariffs imposed on the United States during Mr. Trump’s first term had a negative effect on U.S. jobs, outweighing any benefit to employment from Mr. Trump’s tariffs on foreign goods or from the subsidies Mr. Trump provided to those hurt by his trade policies.

The net effect on American employment of U.S. tariffs, foreign tariffs and subsidies “was at best a wash, and it may have been mildly negative,” the economists concluded.

Rural parts of the country are once again at risk from retaliation. Agriculture is a major U.S. export and farmers are politically important to Mr. Trump. And rural counties may have one major employer — like a poultry processing plant — that provides a big share of the county’s jobs, compared with urban or suburban areas that are more diversified.

The retaliatory tariffs target industries employing 9.5 percent of people in Wisconsin, 8.5 percent of people in Indiana and 8.4 percent of people in Iowa. The shares are also relatively high in Arkansas, Alabama, Mississippi, Kentucky and Kansas.

In an address to Congress earlier this month, Mr. Trump implied that farmers could be hit again, saying there may be “an adjustment period” as he put tariffs in place on foreign products. There may be “a little disturbance,” he said. “We are OK with that. It won’t be much.”

Mr. Trump said he had told farmers in his first term to “‘Just bear with me,’ and they did. They did. Probably have to bear with me again,” he said.

Mark Muro, a senior fellow at Brookings Metro, said that many of the counties affected by retaliation were rural, and “hard red territory.” The geography of Mr. Trump’s political support, he said, was “no secret to our trade partners.”

“They’re very cognizant of these industries, the geography of these industries, and how American politics work,” he added.