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The term sanctuary city returned to the center of the American immigration debate in full force since Donald Trump’s return to the White House in January 2025 and the implementation of the mass deportation program announced during his campaign. For immigrants in undocumented status, temporary status, or even those with a recently issued Green Card, understanding what these jurisdictions are, what they offer, and where they exist has moved from being an academic topic to practical information for daily survival.
There is no single legal definition for sanctuary city or sanctuary state. The concept emerged from practice and refers to jurisdictions that refuse to use local resources to voluntarily assist federal immigration authorities in identifying, arresting, or deporting undocumented immigrants. The policy does not prevent federal operations; it simply refuses to actively cooperate with them.
How the Sanctuary Model Works
A police officer in Boston, Los Angeles, or Chicago has no legal authority to stop ICE or Border Patrol operations in their jurisdiction. Immigration is a federal matter, and the Supreme Court has reaffirmed this primacy in cases such as Arizona v. United States. What a sanctuary city does, within the available constitutional space, is three concrete things.
First, it refuses to honor ICE detainers, administrative requests through which ICE asks a local jail to hold a detainee for up to 48 hours after their release date so that federal agents can pick them up. Since detainers are requests, not court warrants, sanctuary jurisdictions argue that honoring them constitutes detention without probable cause and without a warrant, in violation of the Fourth Amendment.
Second, it limits the sharing of information between municipal departments (police, schools, social services, public hospitals) and ICE. In some places this is an administrative policy; in others, it becomes municipal or state law.
Third, it prohibits local police from asking about immigration status during routine stops, such as a traffic ticket or a domestic violence call. The public health logic here is simple: immigrant communities that fear deportation when calling 911 stop reporting crimes, undermining everyone’s safety.
Which States and Cities Are Sanctuaries
According to a survey by the Center for Immigration Studies, approximately 13 states and more than 220 cities and counties maintain some type of sanctuary policy. The degree varies widely: some prohibit any cooperation, while others only restrict detainers without a warrant.
States with Broad Policies
California (SB 54, known as the California Values Act), Illinois (TRUST Act), Oregon, Washington, Colorado, New Jersey, Massachusetts, Connecticut, Vermont, Rhode Island, Maine, New York, and New Mexico have adopted, to varying degrees, restrictions on cooperation with ICE. Oregon and Illinois are generally considered the most restrictive regarding information sharing.
Cities Historically Declared Sanctuaries
San Francisco, Los Angeles, Chicago, Boston, Philadelphia, Seattle, Portland, Minneapolis, Denver, New York, Newark, and Washington D.C. maintain formal policies. In 2024, Los Angeles converted its 2017 executive directive into a municipal ordinance, shielding the policy from revocation by future mayors.
Anti-Sanctuary States
Texas, Florida, Georgia, Tennessee, Iowa, North Carolina, and Mississippi have moved in the opposite direction. Texas’s SB 4 and Florida’s SB 1718 require local authorities to cooperate with ICE and prohibit cities from adopting sanctuary policies, under penalty of losing state funding.
What Has Changed Since 2025
Shortly after taking office in January 2025, the Trump administration declared a migration emergency, expanded expedited removal authorities, and launched coordinated operations in sanctuary metropolitan areas. Tom Homan took over as border czar, and ICE received authorization to operate in locations previously considered sensitive locations: churches, schools, hospitals, and courthouses.
Cities such as Denver, Chicago, Los Angeles, and Boston became the scene of high-profile operations. The federal government filed lawsuits against Illinois, New York, and California, arguing that sanctuary laws violate the Supremacy Clause. Rulings at the district and appellate court levels have been mixed, and some cases are advancing to the Supreme Court.
At the same time, the government cut or conditioned federal funding to sanctuary jurisdictions under programs such as the Byrne Justice Assistance Grant and the COPS Hiring Program. Litigation over the constitutionality of these cuts remains active in 2026.
What This Means for Immigrants
Being in a sanctuary city is not a legal shield. Federal operations occur in all jurisdictions, and ICE can arrest anyone in a public area or workplace regardless of local policy. What changes is the likelihood and vector of the encounter.
In sanctuary cities, the risk of being handed over to ICE after a local arrest for a minor infraction is lower, though not zero. Local police do not routinely ask about immigration status, and the flow of information between municipal and federal authorities is restricted. In anti-sanctuary jurisdictions, the opposite is true: a traffic ticket can escalate to detention and removal proceedings.
Undocumented immigrants should internalize three basic precautions, valid in any city. Know your rights under the Fourth and Fifth Amendments: the right to remain silent, the right not to open the door without a judicial warrant signed by a judge, and the right to an attorney. Keep important documents in a location known to a trusted family member and have an immigration attorney’s number on hand. Do not sign anything presented by ICE without understanding the content, especially voluntary departure forms (Form I-826) that waive the right to a hearing before an immigration judge.
The Future of the Sanctuary Model
The sanctuary city model is under unprecedented legal, political, and operational pressure. Supreme Court decisions in the coming cycles could drastically reshape the balance between federal and local powers. For immigrants, the lesson is that geography matters, but it is only one variable within a broader protection strategy that includes valid status whenever possible, full registration under the Alien Registration Requirement in effect since March 2025, and active legal counsel.
Victoria Harper
Editor-in-Chief
Leading journalism and editorial content at Visto n’ Visa, Victoria helps make immigration topics clear, trustworthy, and easy to understand. Her focus is on delivering useful, human, and relevant content for people exploring new paths abroad.
