When he was young, Diego Quiñones got so frustrated putting in long hours at his immigrant family’s business that he once kicked over a bucket in protest. He now concedes that his labors were worthwhile. During a tour of his family’s wooden pallet plant near Bentonville, Ark., he beamed with pride noting that business was booming.

Mr. Quiñones, along with his mother and siblings, moved to the United States from Mexico in 1997, two years after his father. Most of them entered illegally. His father is still undocumented. Like other immigrants, the family settled in a part of Arkansas where Walmart has its headquarters and the poultry business is strong. They joked that the pallets used by these local industries were as popular in Bentonville as tortillas were in Mexico — so they started manufacturing them. As the region has grown, their pallet business has too.

No one knows how many Arkansas immigrants, like members of Mr. Quiñones’s family, came here without documents. But former President Donald J. Trump’s party platform promises nationwide the “largest deportation effort in American history.” Some worry about what deportations would mean for Northwest Arkansas’s workers, and the businesses that rely on them.

Northwest Arkansas was last year ranked the 15th fastest-growing region in the country, and much of that population growth is driven by immigrant workers. According to the 1990 census, the region was 95 percent white. By 2021, that figure had fallen to nearly 71 percent. Springdale, where Tyson Foods is based, is now nearly 40 percent Hispanic.

Mr. Trump has offered few details on his plans for mass deportations, though JD Vance, his running mate, said during the vice-presidential debate that they would start with deporting roughly one million people who had crimes on their records other than entering the country illegally.

Immigration experts point out the many barriers to enacting Mr. Trump’s plan, including the sheer size of the population. There were 11 million undocumented immigrants living in the country in 2022. A mass deportation could cost some $88 billion a year over roughly 10 years, according to an estimate from the American Immigration Council, which is a nonprofit advocacy group. Congress would have to come up with the money to carry out one million arrests, including hiring at least 31,000 immigration agents, a researcher for the council said. The legal system is already backlogged: There are nearly four million cases winding their way through the courts, and cases often take two to six years.

Even with those logistical hurdles, the specter of mass deportations has stirred, for many, a sense of fear. Mr. Quiñones’s mother got permanent residency in 2021. He and his sister are part of the Deferred Action for Childhood Arrivals, or DACA, program, which protects immigrants brought to America as young children from deportation.

“It’s a popular selling point to the base to say ‘I’m going to round up five million immigrants,’” said Mr. Quiñones, 35. “You want to cut out your labor source? It seems counterproductive.”

The influx of immigrants into Northwest Arkansas has given rise to a thriving local ecosystem of businesses. Downtown Springdale is dotted with Mexican restaurants, and its school system is 45 percent Hispanic. The city celebrates an annual festival called ArkanSalsa Fest. Last year came the announcement that Arkansas is planning to welcome a professional soccer team, Ozark United FC, whose co-founder said that he saw opportunity because of the region’s population growth and large Hispanic community.

Many economists have taken up the question of how immigration affects the labor market. The answers that emerge are layered. Research shows that immigrants often create jobs by driving up demand for food, cars and services. When economists studied the effects of 400,000 deportations of unauthorized immigrants between 2008 and 2013, they found that for every 100 people removed from the labor market because of deportations, there were nine fewer jobs for U.S.-born workers.

Unauthorized immigrants also fill jobs that native-born workers depend upon but don’t want to do themselves, at least at the wages offered, in fields including child care, construction and agriculture. But other research shows that can have a negative effect on the wages of some U.S.-born workers, like high school dropouts.

The short-term effects of a sudden, large-scale deportation can be jarring. After nearly 400 workers were arrested in the raid of a meatpacking plant in Iowa in 2008, the local economy suffered: The plant filed for bankruptcy and small businesses shut down.

Some business leaders in Arkansas are candid about the potential economic and labor force problems that could arise from mass deportations.

“It would certainly cause disruption and angst,” said Nelson Peacock, who leads the Northwest Arkansas Council, which was created by major employers like Walmart and Tyson to promote economic development.

Seated in a Fayetteville, Ark., coffee shop, Mr. Peacock said his organization hoped to start a program helping regional employers secure legal services for their immigrant workers, especially those who can’t fill out English paperwork or afford legal fees.

Mr. Peacock has observed with alarm the tense national debates about the immigrant community in Springfield, Ohio, which Mr. Vance said has been “overwhelmed” by Haitian newcomers.

“We don’t have this thinking that people are being displaced,” Mr. Peacock said. “We, in fact, have 11,000 open jobs.”

In Northwest Arkansas, Mr. Peacock said, people tend to recognize how much the regional economy depends on its immigrant workers, though he doesn’t think that will stop people from supporting Mr. Trump.

“I don’t know that it weighs into the way people vote,” he added.