Customers entering Zamora Fresh Market are greeted by Spanish-language music and the colorful sight of papel picado hanging from the ceiling of a small dine-in section. Employees chat in Spanish to each other and people buying tortas, lengua de res and containers of arroz y frijoles.

Zamora’s sits on Main Street in Marshalltown, Iowa, about 45 minutes north-east of Des Moines. The market’s presence in the center of town, alongside a number of other Latinx-owned businesses, is a testament to how Marshalltown has been shaped by the waves of immigrants who have arrived in recent decades.

As the Iowa caucuses near, Marshalltown has become a frequent stop for Democratic presidential candidates. In the past month alone, the town has been visited by Elizabeth Warren, Pete Buttigieg and billionaire activist Tom Steyer. When those candidates come to Marshalltown, they face an audience that is more racially diverse than much of Iowa and acutely aware of what’s at stake.

Latinx immigrants first started arriving to Marshalltown in large numbers in the 1990s, seeking jobs at the local meat-processing plant. Today, the Latinx community constitutes nearly 30% of the town’s population of 27,000, compared with 6.2% of Iowa’s total population. The district’s superintendent estimated last year that children of color made up about 70% of incoming kindergarten students.

Local leaders acknowledge many Marshalltown residents are undocumented or “dreamers”, those who came to the US as young children and benefited from the Obama administration’s Deferred Action for Childhood Arrivals (Daca) policy.

Veronica Guevara, a founding member of local group Immigrant Allies of Marshalltown, said the organization aims to dispel myths about the immigration system for residents who have not experienced it firsthand.

But Guevara said the group’s work has shifted since the 2016 election of Donald Trump. “A lot of the work has changed to respond to what’s going on, ever since this president was inaugurated,” Guevara said. “There have just been so many things happening so close together. It’s been really hard to respond and keep people up to date.”

Shortly after Trump’s election, Alfonso Medina Jr, who owns a local restaurant, met Marshalltown officials to ensure they would protect the town’s immigrant community. “Since Trump won, there’s definitely fear. There’s insecurity,” he said “We’re very fortunate to have a very welcoming town.”

Marshalltown residents attending campaign events for the upcoming caucuses spoke with pride about their town being among the most racially diverse in the state. “When we first moved here 20 years ago, it wasn’t that diverse, in terms of businesses,” said Jim Kelehan, 64, just before seeing former secretary of state John Kerry stump for Joe Biden in Marshalltown. “It has really changed a lot and for the better.”

Bernie Sanders in Marshalltown in October. Photograph: Scott Olson/Getty Images

Medina made a point to emphasize that much of Marshalltown’s economy has been made possible by the town’s immigrant community. “Marshalltown would not be where it is today without the Hispanic community,” Medina said. “It’s thriving.”

When it comes to the Democratic presidential race, Medina said that he wished more candidates recognized the direct connection between immigration and the economy, arguing immigrants fill jobs that would otherwise remain open as the unemployment rate remains at a 50-year low.

“They’ll talk about how we need immigration reform, as anybody running always does,” said Medina, who has met Buttigieg and Steyer. “But I think we really do need to make it a reality this time because it’s something that’s a dire need.”

Guevara credited former housing secretary Julián Castro, who suspended his presidential campaign earlier this month, for pushing his primary opponents on the issue of immigration. Castro pledged to decriminalize unauthorized border crossings, a proposal that was adopted by many of his fellow candidates.

But overall, Guevara, who is caucusing for Sanders, said the immigration debate amid the Democratic presidential primary sometimes missed the mark. “A lot of what people ask for sometimes get lost amid all the noise,” she said. “For family members I have who don’t have status, all they want is just to be left alone. They just want peace and to be able to be left alone.”

When Iowans gather to caucus on 3 February, residents of Marshalltown who are undocumented will not be allowed to weigh in on who should face off against Trump in November. However, this administration’s border policies, combined with the president’s anti-immigrant rhetoric, appear to have made those with undocumented loved ones more determined to caucus next month.

“The folks that I talk to, especially the ones with family members that don’t have status, are even more motivated to vote,” Guevara said. “I feel like the general sentiment among a lot of people I know is that it is so important to vote right now.”

Of course, the rarity of towns like Marshalltown in Iowa raises the question of whether it and New Hampshire should continue to vote first at all, given both are mostly white. Castro resurrected this issue late last year, expressing concern about having states that are “not reflective of the US as a whole” vote first in the nominating contest.

On this question, a slight split emerged among some of Marshalltown’s community leaders. Jeannine Grady, the chair of the Marshall County Democrats, noted that Iowans considered their early voting status to be “a bit of a sacred cow”.

“Why do people feel that the first contest has to be reflective of the nation?” she added. “No state accurately reflects the entire nation.”

But Medina, who originally endorsed Castro before backing Warren, agreed with the former housing secretary that a reorganization of the early primary states was worth consideration.

“I’m a firm believer that just because something has been done that certain way doesn’t mean it’s the right way,” Medina said. “I would not have a problem with another state going first instead of Iowa and New Hampshire. I would support it.”