Can Police Arrest Illegal Immigrants: ICE Detainers and 287(g)

Local police generally cannot arrest illegal immigrants based on immigration status alone. Immigration is a federal matter, and the arrest powers that come with it belong to agencies like U.S. Immigration and Customs Enforcement (ICE) and Customs and Border Protection (CBP). Local officers can check a person’s immigration status during an otherwise lawful stop, and in a growing number of jurisdictions they can hold people for ICE or act under delegated federal authority. But the initial arrest by a city or county officer still has to rest on a state or local offense, not on the fact that someone is in the country without authorization.

Why Local Police Lack Direct Immigration Arrest Power

The Supreme Court has repeatedly treated immigration as a federal power. In Arizona v. United States (2012), the Court struck down several Arizona provisions that tried to create state-level immigration offenses, citing the federal government’s “broad, undoubted power over immigration and alien status.”¹ Arizona’s approach conflicted with the framework Congress had already built.²

Federal immigration officers operate under statutory powers local police simply don’t have. Under 8 U.S.C. § 1357, federal officers can question anyone they believe to be a noncitizen about their right to remain in the country without a warrant. They can arrest someone they see entering the country illegally, and they can arrest anyone they reasonably believe is unlawfully present and likely to flee before a warrant can be obtained.³ A local officer’s arrest, by contrast, has to be tied to a violation of state or local law.

Not All Immigration Violations Are Crimes

A common misunderstanding is that being in the country illegally is itself a crime local police can enforce. It depends how the person got there.

Crossing the border without authorization is a federal crime. A first offense carries up to six months in jail; a repeat offense carries up to two years.⁴ Re-entering after a formal deportation is more serious: up to two years in prison, or up to 20 years if the person was previously convicted of an aggravated felony.⁵

Overstaying a visa is different. Someone who entered legally but stayed past their authorized period has committed a civil violation, not a crime. The consequences can be severe, including removal and long bars on re-entry, but they run through civil immigration proceedings.⁶ Local police enforce criminal law. They do not run civil immigration proceedings, and even the criminal entry offenses are prosecuted by federal attorneys, not local district attorneys.

What Local Officers Can Do During a Lawful Stop

Arizona v. United States preserved one significant tool. The Court upheld Section 2(B) of the Arizona law, which allows officers to check a person’s immigration status during a lawful stop, detention, or arrest when the officer has reasonable suspicion that the person is unlawfully present.¹

The word doing the work is “lawful.” The stop has to originate from something else: a traffic violation, a criminal investigation, an outstanding warrant. An officer cannot pull someone over or detain them on the sidewalk specifically to ask about immigration status. The Court also flagged built-in constraints. A valid state-issued driver’s license or similar ID creates a presumption of legal status, officers cannot use race or ethnicity as a basis for suspicion, and any inquiry must be consistent with federal law.⁷

There’s also a time limit. In Rodriguez v. United States (2015), the Supreme Court held that police cannot extend a traffic stop beyond the time reasonably needed to handle the original violation, absent independent reasonable suspicion of other wrongdoing.⁸ Once the ticket is written, or reasonably should have been written, the authority for the stop expires. An officer who then launches into immigration questions without a separate basis for suspicion is on shaky constitutional ground.

If a status check during a valid stop does reveal that someone is undocumented, the local officer still books the person on the state or local offense, not on the immigration violation. The officer contacts ICE, and ICE decides whether to take custody.

When Local Police Effectively Do Enforce Immigration Law

Two federal mechanisms let local agencies become part of immigration enforcement in practice, even though they lack independent arrest authority. Both have expanded sharply since early 2025.

ICE Detainers

An ICE detainer is a written request from ICE asking a local jail to hold someone up to 48 hours past their scheduled release, giving federal agents time to pick the person up.⁹ It is a request, not a court order. Local facilities are not legally required to comply, and multiple federal courts have found that holding someone past their release date on a detainer alone, without a judicial warrant or independent probable cause determination, can violate the Fourth Amendment. Practice varies widely by jurisdiction.

287(g) Agreements

The 287(g) program goes further. ICE trains and authorizes local law enforcement officers to perform specific immigration functions under federal supervision. Participating agencies sign a formal agreement and operate under one of two models.¹⁰

Under the Jail Enforcement Model, deputized officers question people booked into the jail about their immigration status and can issue ICE detainers for those identified as removable.
Under the Warrant Service Officer Model, local officers serve and execute administrative immigration warrants on people already held in their facility.

The scale has changed quickly. As of early 2026, ICE reported over 1,400 active 287(g) agreements across 40 states and territories, up from roughly 111 jail enforcement agreements in mid-2025.¹⁰ If your local sheriff’s office participates, being booked on any charge, even a minor one, can trigger a direct pipeline to federal immigration enforcement.

The Laken Riley Act

Signed in January 2025, the Laken Riley Act requires ICE to detain any noncitizen who is unlawfully present and has been charged with, arrested for, or convicted of burglary, theft, larceny, or shoplifting.¹¹ Before this law, detention for lower-level property offenses was discretionary. A shoplifting arrest that once might have ended with a citation and a court date can now lead to mandatory immigration detention if the person is undocumented. The local officer still makes the initial arrest on the state charge; the federal consequences follow.

Border Patrol Is a Different Story

Don’t confuse local police powers with Border Patrol’s. Federal regulations authorize immigration officers to board and search vehicles without a warrant within 100 air miles of any U.S. external boundary, which includes coastlines, not just the southern border. Within that zone, Border Patrol runs permanent and temporary checkpoints where agents can briefly question vehicle occupants about citizenship and request documentation. The Supreme Court upheld these checkpoints in United States v. Martinez-Fuerte (1976).¹²

Agents at checkpoints can ask brief questions and observe what’s visible inside the vehicle, but a full vehicle search still requires probable cause. You can decline a search request, though refusing to answer citizenship questions may prolong the detention while agents work to verify status. Outside the 100-mile zone, roving Border Patrol units can still stop vehicles, but only with reasonable suspicion of an immigration violation or crime.

Sanctuary Policies and Why Location Matters

Some cities and counties have moved in the opposite direction, adopting sanctuary policies that limit local cooperation with immigration enforcement. These policies vary, but they commonly restrict local officers from asking about immigration status and instruct jails not to honor ICE detainers. The stated reasoning is practical: people who fear deportation won’t call 911, report crimes, or come forward as witnesses.

Federal law draws a line. Under 8 U.S.C. § 1373, no state or local government can prohibit its employees from sharing immigration status information with federal authorities.¹³ A sanctuary city can tell its officers not to actively investigate immigration status, but it cannot bar them from communicating information they already have to ICE.

An April 2025 executive order directed federal agencies to publish a list of jurisdictions that “obstruct the enforcement of Federal immigration laws” and identify federal funding eligible for suspension or termination from those places.¹⁴ The practical result is that whether local police cooperate with ICE, honor detainers, or actively check status varies significantly by where you are.

Your Rights If a Police Officer Stops You

Every person in the United States has constitutional protections during police encounters, regardless of immigration status.

You are not required to answer questions about where you were born, your citizenship, or how you entered the country. If you want to invoke that right, say so out loud: “I am exercising my right to remain silent.”¹⁵
If you are arrested, ask for a lawyer immediately and stop answering questions until one is present.
You do not have to consent to a search of your person, vehicle, or home. Saying “I do not consent to a search” does not guarantee the officer stops, but it preserves your legal arguments later.
You are not required to show immigration documents or a foreign passport to a local officer. Never present false documents; that’s a separate federal crime.

During a traffic stop, the driver may be required by state law to show a license, registration, and proof of insurance. Passengers are generally not required to identify themselves during a routine stop, though this varies by jurisdiction. The stop cannot be extended beyond its original purpose to investigate immigration status unless the officer develops separate reasonable suspicion.⁸

At a Border Patrol checkpoint within the 100-mile zone, the rules shift. Agents can ask brief citizenship questions, and declining to answer may lead to a longer detention. Even so, agents cannot search your vehicle without probable cause or your consent.¹²

Stay calm, don’t run, don’t physically resist, and don’t lie. What you say in the first few minutes can shape everything that follows.

1
Cornell University. Arizona v. United States
2
Constitution Annotated. ArtI.S8.C18.8.8.5 Immigration-Related State Laws
3
GovInfo. 8 USC 1357 – Powers of Immigration Officers and Employees
4
Office of the Law Revision Counsel. 8 USC 1325 – Improper Entry by Alien
5
Office of the Law Revision Counsel. 8 U.S. Code 1326 – Reentry of Removed Aliens
6
Department of Justice Archives. 1911 8 USC 1325 – Unlawful Entry, Failure To Depart, Fleeing Immigration Checkpoints, Marriage Fraud, Commercial Enterprise Fraud
7
Justia U.S. Supreme Court. Arizona v. United States, 567 U.S. 387 (2012)
8
Justia U.S. Supreme Court. Rodriguez v. United States, 575 U.S. 348 (2015)
9
U.S. Immigration and Customs Enforcement. Immigration Detainers
10
U.S. Immigration and Customs Enforcement. Delegation of Immigration Authority Section 287(g) Immigration and Nationality Act
11
Congress.gov. S.5 – Laken Riley Act
12
help.CBP.gov. Legal Authority for the Border Patrol
13
Office of the Law Revision Counsel. 8 U.S. Code 1373
14
The White House. Protecting American Communities from Criminal Aliens
15
Constitution Annotated. Fifth Amendment – Right to Remain Silent