The U.S. Immigration and Customs Enforcement (ICE) is a federal law enforcement agency under the U.S. Department of Homeland Security. ICE's stated mission is to protect the United States from the cross-border crime and illegal immigration that threaten national security and public safety.

The ICE mission is executed through the enforcement of more than 400 federal statutes and focuses on customs violations, immigration enforcement, preventing terrorism and combating the illegal movement of people and goods. ICE has two primary and distinct law enforcement components, namely, Homeland Security Investigations (HSI) and Enforcement and Removal Operations (ERO); in addition to three supporting divisions: Management & Program Administration, Office of Principal Legal Advisor (OPLA) and Office of Professional Responsibility (OPR).

Enforcement and Removal Operations (ERO), which primarily deals with the deportation and removal of undocumented non-citizens, is among the most public and contentious function of ICE. ERO maintains the custodial facilities used to detain people that are illegally present in the United States. In interior offices, ERO officers primarily conduct targeted enforcement operations to apprehend aliens engaged in serious criminal activity. For example, in fiscal year 2020, 90% of those aliens apprehended by ERO had criminal convictions or pending charges at the time of their administrative arrest. This FY 2020 arrest statistic includes 1,800 homicide related offenses, 1,600 kidnappings, 3,800 robberies, 37,000 assaults, and 10,000 sex crimes. At border offices ERO officers receive and detain illegal immigrants apprehended by Border Patrol. Illegal immigrants apprehended at the border have significantly lower levels of criminal history than those arrested by ERO in the interior of the United States.

ICE maintains domestic offices throughout the United States and attachés at major U.S. diplomatic missions overseas. ICE personnel (special agents and officers) do not patrol American borders; rather, that role is performed by the United States Border Patrol. ERO and HSI operate as two independent law enforcement agencies and have completely separate mission statements. HSI is focused on the disruption of transnational crime, where as ERO is responsible for the apprehension, detention and removal of illegal immigrants.

The Acting Director is Tae Johnson. The agency has not had a Senate-confirmed director since Sarah Saldaña stepped down on January 20, 2017.