Long a jumping-off point for immigrants, the neighborhood has more than 500 previously empty homes occupied by refugee families, according to State Assemblyman Sean Ryan, a Democrat who represents the area. New businesses reflect that new diversity: The West Side Bazaar, “an international small-business incubator” teeming with food stands, does a healthy business, as does a local grocery offering fruits, vegetables and “worldwide money transfer.” A new local newspaper, The Karibu News, publishes in at least six languages.

While Mr. Trump’s order has been stayed by federal courts, the turmoil surrounding it has nevertheless unsettled both the refugee and the resettlement communities.

Dennis C. Walczyk, chief executive of Catholic Charities of Buffalo, said that the president’s order had spread suspicion among new arrivals. “They’re questioning us,” Mr. Walczyk said, adding: “Even though we’re all independent, nonprofit, nongovernmental agencies, the connection seems to be being made by some of our clientele, that, ‘Well, you’re an arm of the government.’”

Groups like Mr. Walczyk’s do receive an administrative payment for their work in settling new arrivals — $900 per person — and the potential loss of that money is another point of concern, though refugee placements have restarted. Some resettlement groups across the state have already tightened their belts, and reduced staffs, reflecting President Trump’s immigration order and his administration’s plan to accept 50,000 refugees this federal fiscal year, as opposed to the target of 110,000 set by President Barack Obama. (One small upside of the order, however: Groups say donations and volunteerism are up.)

Eva M. Hassett, the executive director of the International Institute of Buffalo, another resettlement agency, says she fears that the changes proposed by the new administration would imperil the city’s longstanding reputation for welcoming newcomers, something that dates back to waves of Italian, Irish and Eastern European immigrants who followed the trains and canals west in the 19th and 20th centuries.