Sanctuary City Mayors to Face Congress: How Many Migrants Did They Welcome?

Four Democratic mayors of "sanctuary cities" are set to face members of Congress Wednesday, as their immigration policies are scrutinized by Republicans who believe they are getting in the way of federal agents.

New York City's Eric Adams, Boston's Michelle Wu, Denver's Mike Johnston and Chicago's Brandon Johnson were all summoned to the House Oversight Committee to justify their stances on not allowing local police and other agencies to help with immigration enforcement.

"Sanctuary jurisdictions and their misguided and obstructionist policies hinder the ability of federal law enforcement officers to effectuate safe arrests and remove dangerous criminals from American communities, making Americans less safe," Kentucky Representative James Comer, chairman of the House Oversight and Government Reform Committee, said after announcing the hearing in January.

Why It Matters

President Donald Trump views sanctuary jurisdictions, including cities, counties and states, as barriers to his sweeping immigration enforcement plans—which many voters supported during and after the election campaign, including the mass deportation of millions of illegal immigrants. Most of those jurisdictions are Democrat run.

What To Know

The hearing will take place at 10 a.m. ET Wednesday on Capitol Hill, with Comer asking the four mayors to provide documents and communications related to their sanctuary policies ahead of time.

The Republicans on the committee argue that the four cities—New York, Boston, Chicago and Denver—are emblematic of the way similar jurisdictions across the country "take it upon themselves" to decide which federal laws to abide by.

Immigration enforcement has long been the responsibility of the federal government, a role upheld by various Supreme Court decisions. In recent years, however, some GOP-led states have taken it upon themselves to aid in the effort to detain illegal immigrants and place restrictions on those without legal status. Democrat-led states, meanwhile, have pushed back with the so-called sanctuary policies.

What Are Sanctuary Policies?

While some sanctuary policies developed around 40 years ago, the idea gained wider traction in the early 2000s and 2010s as the country's immigration system changed in the wake of the September 11 attacks. Many migrants, especially those without legal status, grew more fearful of seeking help from law enforcement, healthcare providers and other support services. Establishing and expanded "sanctuaries" where they would not need to fear being deported came in response to that.

"More and more states and localities were seeing families torn apart in their communities, their economies undermined by people being ripped out of their communities, businesses losing workers, families losing breadwinners and, acutely, at that time, the primary gateway into the deportation pipeline for people in many immigrant communities was local police departments," said Peter Markowitz, an immigration law professor at Cardozo Law School who helped to write New York City's sanctuary policy in 2009.

No sanctuary policy is the same, and each locality has adopted different rules over time, but most were born out of the issues noted by Markowitz.

Chicago adopted its policy in 1985, through an executive order by Mayor Harold Washington. The order prevented city workers and police from questioning residents about their immigration status and stopped them working with federal agents. The policy has been both strengthened and loosened over time, allowing police to work with agents at different points.

Boston's policy is codified in law under the Boston Trust Act, which stops police from detaining individuals solely based on their immigration status. Officers can only work with Immigration and Customs Enforcement (ICE) in matters of "significant public safety" threats.

Similar policies have also been adopted in New York City, while Denver has never directly approved a sanctuary policy, but did declare itself a city "welcoming and inclusive of all people" in 2016.

New York state's sanctuary policies, now under scrutiny by the Department of Justice (DOJ), include allowing immigrants in the country illegally to obtain a driver's license.

Markowitz said that many sanctuary localities have been shown to be safer than those which are not, and have shown results in keeping law-abiding residents protected from what he called ICE overreach.

"Because of their effectiveness, they have now become the target of this administration," the professor said.

How Many Migrants Did Sanctuary Cities Welcome?

The four sanctuary cities became one of the key focuses of the border crisis as it unfolded from early 2022. With record numbers of illegal crossings at the U.S.-Mexico border, many were bussed to these cities from Republican states like Texas and Florida — a political stunt widely seen as effective in giving national attention to the strains taken on by border communities that dealt with the influx of new migrants.

NYC likely saw the most, with over 232,000 documented new arrivals in that time period. Many were housed in temporary shelters across the city, including at the Roosevelt Hotel, a one-time luxury hotel that had fallen into disrepair in midtown Manhattan. The city spent over $7 billion on housing, food, education, and other support services.

Chicago also welcomed several thousand, thought to be around 31,500. Many arrived from other parts of the country, overwhelming a city without the shelter space NYC had. Hundreds slept outside police stations or at O'Hare International Airport.

Denver welcomed around 42,911 immigrants from December 2022 through October 2024, when it closed all of its short-term shelters. In July 2024, the city said it had spent more than $72 million on services for migrants. The federal government reimbursed Denver for at least $1.6 million of that sum.

Figures for Boston are harder to come by. Massachusetts overall saw its population rise at the fastest rate in 60 years between 2023 and 2024, largely because of refugee and other migrant arrivals. It was estimated that around 54,000 immigrants entered the state between 2022 and 2023.

Why Is the Trump Administration Against Sanctuary Cities?

The president, his border czar Tom Homan, and the wider Republican Party have been vocal in what they see as the illegality of sanctuary policies, arguing they stand in the way of ICE and other federal agents doing their jobs.

Markowitz said this was a "deliberate communication strategy" to make it seem that sanctuary policies stood in the way of national security.

ICE raids still take place in sanctuary cities. Often, when an illegal immigrant is a known violent offender, local police departments can cooperate with ICE and hand them over.

Homan has said sanctuary policies prevent that, and there are examples of times when detainers lodged by ICE have gone ignored, particularly in Boston and wider Massachusetts.

The Trump administration has also said that those who entered the U.S. illegally, or whose status has lapsed, are by definition criminals and therefore can be deported.

"There is nothing in the [Immigration and Nationality Act] that says you got to be convicted of a serious crime in order to be removed from this country," Homan told CNN's Dana Bash in January. "So, there's going to be more collateral arrests in sanctuary cities because they forced us to go into the community and find the guy we're looking for."

What Have the Sanctuary Mayors Said?

While Adams maneuvered NYC's resources to look after newly arrived immigrants, he became increasingly frustrated with former President Joe Biden's administration for what he saw as a lack of assistance in dealing with the growing crisis. Repeated calls for federal funding appeared to go unanswered.

In recent weeks, with federal corruption charges appearing to no longer hang over him, Adams has spoken with both Trump and Homan about how the city can assist federal immigration agents seeking to arrest known criminals.

"I'm not standing in the way; I'm collaborating against so many others who don't want to collaborate," Adams said in an appearance with Homan on Fox News. "I've said it over and over again, we need to control our borders."

The other mayors are taking a different posture. Denver's Mike Johnston recently told City Cast Denver that his administration was "preparing very thoroughly to make the case for the policies we have in Denver and why we think they are a common-sense approach to this challenge".

Boston's Michelle Wu said Monday that she was ready to testify on behalf of a city where 28 percent of residents were born in a different country.

"I am going to represent the City of Boston, the amazing people who live here, work here who are making our community wonderful," she told reporters. "I'm there no matter how challenging the circumstance is to stand up for Boston and also stand up for the truth, the facts of what we are."

Chicago's Brandon Johnson has also said he will seek to uphold the values he believes Chicago shares.

"Whether or not we can get our message across in that particular room doesn't mean that I'm going to stop delivering the message of hope," Johnson told reporters last week. "I don't care which congressperson believes in that or not. It doesn't sway my belief that there are good, decent people in this city and across America who deserve their government to show up for them."

What People Are Saying

Eric Adams' Press Secretary Kayla Mamelak Altus told Newsweek: "We are proud of this work, but let's be clear: No city should ever be left largely alone to manage this sort of crisis, and the federal government must finally step up and pass comprehensive immigration reform.

"Mayor Adams believes in protecting law-abiding New Yorkers who are doing nothing more but contributing to bettering our way of life and helping our city run. However, those who commit crimes in our city should be removed from our streets, which is why the mayor has also been clear that we must continue to remove violent criminals from our streets."

Markowitz, speaking to Newsweek: "Adams seems ill-positioned to be the one to present the cold hard facts about the reality of what our sanctuary laws have done to the city. The reality is that if you look at the decade before the implementation of these laws and the decade after the implementation of these laws, what you see is 90,000 fewer major felony crimes in that period."

What's Next

With the televised hearing due to take place Wednesday, Republicans are also pursuing a bill in Congress to strip federal funding from sanctuary cities. The DOJ has also begun legal action against Chicago and Illinois, and New York state over their policies, with more civil lawsuits possible.

Correction 03/05/25 12:06 p.m. ET: The spelling of Denver Mayor Mike Johnston's name has been corrected; a previous version had Johnson.