ICE stands for U.S. Immigration and Customs Enforcement, a federal law enforcement agency inside the Department of Homeland Security. It has two jobs: enforcing immigration law in the interior of the country and investigating cross-border criminal activity like smuggling, human trafficking, trade fraud, and cybercrime. Those two jobs sit in two separate divisions, which is why ICE can look like very different agencies depending on which one you happen to encounter.1LII. Immigration and Customs Enforcement (ICE)
Where ICE Came From
ICE did not exist before 2003. Until then, a single agency called the Immigration and Naturalization Service handled both the paperwork side of immigration (green cards, citizenship applications) and the enforcement side (arrests, deportations, investigations). The Homeland Security Act of 2002 broke INS apart and moved the pieces into the new Department of Homeland Security.
The paperwork functions went to U.S. Citizenship and Immigration Services. Screening people and goods at ports of entry went to Customs and Border Protection. Interior immigration enforcement and customs-related criminal investigations were combined into ICE. The reorganization was a post-9/11 response to what Congress viewed as gaps between border security, interior enforcement, and criminal investigation.1LII. Immigration and Customs Enforcement (ICE)
How ICE Differs From CBP and USCIS
All three agencies sit under DHS, and people mix them up constantly. The clearest way to keep them straight is by where the work happens and what it looks like.
CBP works at and near the border. Its officers screen travelers at airports, seaports, and land crossings, and the U.S. Border Patrol (part of CBP) patrols the areas between official crossings. USCIS is the benefits agency: it decides applications for green cards, work permits, naturalization, and asylum. ICE works inside the country. Its officers arrest people subject to removal orders, run immigration detention facilities, audit employers, and run federal criminal investigations that reach across the border. Enforcement at the border is usually CBP. Arrests at a workplace or a home in the interior are usually ICE.
The Two Divisions of ICE
Nearly everything ICE does falls under one of two operational arms. They report to the same agency, but they draw on different authorities and go after different targets.
Enforcement and Removal Operations (ERO)
ERO is the division most people picture when they hear “ICE.” ERO officers locate, arrest, and deport noncitizens who are in the country without authorization or who have final orders of removal from an immigration judge. The division runs immigration detention facilities, transports detainees between facilities and courts, and carries out deportation flights. ERO is also the office that issues immigration detainers to local jails.2Department of Homeland Security. Immigration Detainer – Notice of Action
Homeland Security Investigations (HSI)
HSI is the criminal investigative side. It has roughly 6,000 special agents in 235 offices across the United States and additional agents posted at U.S. embassies overseas.3U.S. Immigration and Customs Enforcement. Our Offices HSI investigates transnational crime: human trafficking, drug smuggling, money laundering, intellectual property theft, child exploitation, and cybercrime. It runs the National Intellectual Property Rights Coordination Center, which tracks counterfeit goods online and on the dark web.4ICE. Intellectual Property Theft and Commercial Fraud HSI agents also sit on FBI-led Joint Terrorism Task Forces around the country, contributing immigration-related intelligence to counterterrorism work.5U.S. Immigration and Customs Enforcement. Joint Terrorism Task Force HSI leads DHS work against human trafficking and forced labor through its Center for Countering Human Trafficking.
Where ICE’s Authority Comes From
ICE’s immigration powers come mainly from the Immigration and Nationality Act. Section 287 of the INA, at 8 U.S.C. § 1357, lets immigration officers question anyone they believe is a noncitizen about their right to be in the United States, make warrantless arrests when they have reason to believe someone is unlawfully present and likely to flee, and issue detainers for people already in custody on other charges.6Office of the Law Revision Counsel. 8 USC 1357 – Powers of Immigration Officers and Employees
Section 236, at 8 U.S.C. § 1226, authorizes ICE to arrest and detain noncitizens while their removal cases are pending, and sets a statutory minimum bond of $1,500. The same section identifies categories of people subject to mandatory detention who generally cannot be released at all, including those convicted of aggravated felonies, drug offenses, firearms violations, and terrorism-related crimes.7Office of the Law Revision Counsel. 8 USC 1226 – Apprehension and Detention of Aliens
On the customs side, HSI’s investigative authority reaches back to the Tariff Act of 1930, which created the framework for going after smuggling and trade fraud.
How ICE Operates in the Interior
Beyond direct arrests, ICE relies on a handful of specific tools to identify and take custody of people it wants to remove, and to press employers to police their own hiring.
Civil Detainers
When ICE learns that someone it believes is removable is sitting in a local jail on other charges, it sends the jail a Form I-247A, called a civil detainer. The detainer asks the jail to hold the person up to 48 hours past their scheduled release so ICE can pick them up.2Department of Homeland Security. Immigration Detainer – Notice of Action Detainers are administrative requests, not judicial warrants, and several federal courts have found that holding someone on a detainer alone can raise Fourth Amendment problems. That is one reason many jurisdictions with sanctuary policies decline to honor them.
287(g) Agreements
Under 8 U.S.C. § 1357(g), ICE can enter written agreements with state and local law enforcement, training and deputizing their officers to perform certain immigration enforcement functions. Some agreements let jail staff screen inmates for immigration violations. Others let local officers identify potentially removable individuals during regular police work. A separate warrant service program authorizes local officers to serve ICE administrative warrants on people already in their custody.8U.S. Immigration and Customs Enforcement. Partner With ICE Through the 287(g) Program
Sanctuary Policies
A range of cities, counties, and states have adopted policies limiting cooperation with ICE. Some refuse to honor detainer requests, some decline to share information about individuals’ immigration status, and some bar the use of local resources for federal immigration enforcement. Federal law under 8 U.S.C. § 1373 prohibits local governments from restricting communication with federal authorities about a person’s immigration status, and the federal government has repeatedly challenged sanctuary policies on that basis.9Office of the Law Revision Counsel. 8 USC 1373 – Communication Between Government Agencies and the Immigration and Naturalization Service
Employer Audits
ICE enforces immigration law against businesses as well as individuals. Every U.S. employer has to complete a Form I-9 for each new hire, documenting identity and work eligibility. HSI can open a formal audit by serving a Notice of Inspection, which gives the employer at least three business days to produce its I-9 records along with payroll lists and other supporting documents.10U.S. Immigration and Customs Enforcement. Form I-9 Inspection Under Immigration and Nationality Act Section 274A Violations trigger civil fines under 8 U.S.C. § 1324a, and employers who show a pattern of knowingly hiring unauthorized workers can face criminal penalties.11Office of the Law Revision Counsel. 8 USC 1324a – Unlawful Employment of Aliens
Your Rights in an ICE Encounter
Constitutional protections apply during any encounter with ICE, whether you are a citizen, a lawful permanent resident, or undocumented. The pressure of the moment leads a lot of people to waive rights they didn’t know they had.
The Fourth Amendment protects your home. ICE agents cannot force their way into a residence without a warrant signed by a federal judge or magistrate. ICE often uses administrative warrants (Form I-200 or I-205) signed by ICE supervisors, not judges. An administrative warrant is not the same as a judicial warrant, and you are not legally required to open your door based on one alone. You can ask agents to slide the warrant under the door so you can see who signed it.
You also have the right to remain silent. You do not have to answer questions about where you were born, how you entered the country, or your immigration status. Saying so clearly matters: “I am exercising my right to remain silent.” You have the right to speak with an attorney before answering questions, and if you are detained, you can contact your country’s consulate for help finding one. During a worksite operation, the same protections apply at work: agents cannot search or seize beyond what their warrant authorizes, and employees keep their right to silence and to counsel.
Detention, Bond, and Limits on ICE Custody
People arrested by ICE are usually placed in a detention facility while their immigration case is pending. ICE uses federally owned facilities, contracted private facilities, and local jails operating under intergovernmental agreements, all governed by the Performance-Based National Detention Standards.12U.S. Immigration and Customs Enforcement. 2011 Operations Manual ICE Performance-Based National Detention Standards
Most people in ICE custody can request release on bond. Under 8 U.S.C. § 1226(a), an immigration judge or ICE can set a bond of at least $1,500. In practice, bonds usually fall somewhere in the $5,000 to $15,000 range, though they can go higher. The judge looks at whether the person is a danger to the community and whether they are likely to appear at future hearings. Mandatory detention under § 1226(c) blocks bond entirely for people convicted of certain offenses.7Office of the Law Revision Counsel. 8 USC 1226 – Apprehension and Detention of Aliens
ICE cannot hold someone indefinitely, even after a final removal order. In Zadvydas v. Davis, the Supreme Court read the post-removal detention statute to allow custody only for a period reasonably necessary to carry out removal, setting a presumptive six-month limit. After six months, if the person can show there is no significant likelihood of removal in the reasonably foreseeable future, ICE has to justify keeping them or let them go.13Cornell Law Institute. Zadvydas v Davis This most often comes up when a person’s home country will not accept them back.
Oversight and Discretion
ICE has broad enforcement discretion, but it is not outside judicial review. Federal courts have set boundaries on how long the agency can detain someone, and class-action suits over inadequate medical care and other conditions in detention have produced court-ordered reforms and ongoing monitoring. Habeas corpus petitions in federal court remain the main way to challenge the legality of detention itself.
Enforcement priorities shift with each administration. ERO generally focuses resources on people charged with or convicted of crimes, immigration fugitives, and national security cases, but the breadth of enforcement varies significantly depending on who sets policy. ICE’s Office of the Principal Legal Advisor reviews individual cases for prosecutorial discretion, so not every removable person ICE encounters will be placed in proceedings. That discretion is one of the most politically contested parts of the agency’s work.