ICE: Immigration and Customs Enforcement Under DHS

U.S. Immigration and Customs Enforcement (ICE) is a federal law enforcement agency operating within the Department of Homeland Security that carries principal responsibility for immigration enforcement in the interior of the United States and for cross-border criminal investigations. Established in 2003 under the Homeland Security Act of 2002 (Pub. L. 107-296), ICE is one of the largest investigative agencies in the federal government, employing more than 20,000 personnel across offices in all 50 states and in more than 50 countries. Understanding ICE's structure, authorities, and operational limits is essential for anyone navigating DHS immigration enforcement policy or tracking how federal law is applied to non-citizen populations.

Definition and scope

ICE is formally composed of two primary operational directorates: Homeland Security Investigations (HSI) and Enforcement and Removal Operations (ERO). A third component, the Office of the Principal Legal Advisor (OPLA), provides litigation support before the immigration courts and the Board of Immigration Appeals.

Homeland Security Investigations (HSI) is the criminal investigative arm. HSI agents hold dual authority to investigate both immigration-related crimes and a broad range of federal offenses including human trafficking, narcotics smuggling, financial crimes, cybercrimes, and export control violations. HSI operates the Homeland Security Investigations mission independently of removal operations, a structural distinction that matters when evaluating agency priorities.

Enforcement and Removal Operations (ERO) manages the identification, arrest, detention, and removal of non-citizens who have violated immigration law. ERO coordinates the supervised release of individuals awaiting immigration proceedings and manages ICE's network of detention facilities, which held an average daily population exceeding 34,000 detainees in fiscal year 2023 (ICE Fiscal Year 2023 Enforcement and Removal Operations Report).

ICE derives its legal authority primarily from the Immigration and Nationality Act (INA), codified at 8 U.S.C. § 1101 et seq., and from Title 19 of the U.S. Code for customs-related enforcement.

How it works

ICE operations follow a structured enforcement chain with defined legal thresholds at each stage:

1. Identification — ERO officers identify potentially removable individuals through database queries (including IDENT/HART biometric systems), referrals from U.S. Customs and Border Protection (CBP), tips from state and local law enforcement, and self-referrals through the immigration court system.
2. Administrative arrest — Unlike criminal arrests, immigration detentions are administrative in nature. An ICE officer may arrest a non-citizen without a judicial warrant if the officer has reason to believe the individual is removable (8 U.S.C. § 1357(a)(2)).
3. Detention or alternatives — Individuals may be held in ICE detention, released on bond, or enrolled in the Alternatives to Detention (ATD) program, which used GPS ankle monitoring and telephonic reporting for more than 180,000 participants in FY2023 (ICE FY2023 ERO Report).
4. Removal proceedings — Cases proceed before the Executive Office for Immigration Review (EOIR), an entity within the Department of Justice, not DHS. ICE's OPLA attorneys represent the government in removal hearings.
5. Final removal — Upon a final order of removal, ERO arranges deportation, coordinating with foreign consulates for travel documents when a receiving country's cooperation is required.

ICE also coordinates with CBP on border-adjacent enforcement and with USCIS when benefits fraud or status violations trigger enforcement referrals.

Common scenarios

ICE enforcement activity occurs across a set of recurring operational contexts:

• Interior enforcement actions — ERO conducts targeted operations against individuals with prior criminal convictions, existing removal orders, or active immigration violations. In FY2023, ICE ERO made 170,590 arrests, of which 70 percent involved individuals with criminal convictions or pending criminal charges (ICE FY2023 ERO Report).
• Worksite enforcement — HSI investigates employers who knowingly hire unauthorized workers, often pursuing criminal charges against employers rather than workers alone. Worksite investigations intersect with the DHS E-Verify program, which provides an electronic employment eligibility verification system.
• Human trafficking investigations — HSI is the primary federal agency investigating labor and sex trafficking. The DHS Blue Campaign operates in partnership with HSI to identify victims and support prosecutions.
• Transnational criminal organization (TCO) disruption — HSI pursues financial networks and supply chains linked to cartels, using asset forfeiture, money laundering statutes, and international liaison offices to dismantle cross-border criminal enterprises.
• 287(g) partnerships — Under Section 287(g) of the INA, ICE enters into agreements with state and local law enforcement agencies that delegate limited immigration enforcement authority to those agencies. As of 2023, more than 150 active 287(g) agreements were in place (ICE 287(g) Program).

Decision boundaries

ICE's authority is bounded by legal, geographic, and policy constraints that distinguish it from both CBP and USCIS:

ICE vs. CBP — CBP holds primary enforcement authority at and within 100 miles of U.S. borders and ports of entry. ICE ERO holds primary authority for interior enforcement — actions occurring beyond that border zone. In practice, coordination agreements bridge this geographic boundary, but legal jurisdiction anchors each agency's primary mandate.

ICE vs. USCIS — USCIS adjudicates immigration benefits (visas, green cards, asylum). ICE enforces immigration law against those who have violated status conditions or removal orders. USCIS does not conduct arrests or removals; ICE does not adjudicate benefits.

Enforcement priorities — ICE enforcement priorities shift with each administration through prosecutorial discretion policies. The Biden administration's 2021 guidance from then-Acting Director Tae Johnson directed ERO to focus resources on national security threats, recent border crossers, and individuals with serious criminal histories — a contrast to prior administrations' broader enforcement mandates. Federal courts have periodically enjoined or upheld such priority directives, reflecting ongoing constitutional litigation over executive discretion in immigration enforcement.

Sensitive locations — ICE policy, not statute, restricts enforcement actions at schools, churches, hospitals, and similar locations absent exigent circumstances (ICE Sensitive Locations Policy). This policy boundary is subject to revision by agency leadership through directive rather than legislation.

The DHS organizational structure places ICE as a component agency reporting to the Secretary of Homeland Security, meaning significant policy shifts require either statutory change or secretarial direction reviewed through the DHS Secretary and leadership chain.