What legal authority allows ICE to detain noncitizens in public places?

1. Statutory backbone: warrantless interrogation and arrest power

Congress authorized immigration officers to question and seize noncitizens in the interior U.S.; notably 8 U.S.C. § 1357(a) permits an immigration officer, without a judicial warrant, to “interrogate any alien or person believed to be an alien” and to make arrests for violations of immigration law, a statutory text repeatedly cited in legal primers and congressional summaries as the primary source of ICE’s authority to conduct interior enforcement ^[1].

2. Administrative warrants: internal authorization for civil arrests in public

For civil immigration violations—being in the country without lawful status—ICE typically relies on administrative warrants signed by ICE officials rather than judicial warrants; legal guides and mainstream reporting explain that those administrative warrants authorize arrests and operations in public or publicly accessible areas but do not generally permit forcible entry into private homes or nonpublic spaces absent additional legal process ^{[2] [3]}.

3. Public vs. private spaces: where ICE can operate without consent

Across agency guidance and legal aid resources, a clear pattern emerges: ICE and police may enter and operate in public areas (lobbies, parking lots, sidewalks and other spaces where there is no expectation of privacy) without organizational permission, and arrests in such public places are routine and lawful, whereas entry into private, nonpublic spaces typically requires either the property owner’s consent or a judicial warrant authorizing such intrusion ^{[4] [5] [6]}.

4. Constitutional and judicial limits: the Fourth Amendment and court rulings

Constitutional law imposes limits: the Fourth Amendment’s protection against unreasonable searches and seizures applies to immigration arrests and detentions, and several lower courts have held that ICE cannot enter homes without a judicial warrant even if it holds an administrative ICE warrant; moreover, courts have required prompt probable‑cause determinations when detention follows immigration arrest, signaling judicial constraints on how ICE exercises its statutory power ^{[3] [1] [7]}.

5. Operational tools and partnerships that extend reach: detainers and coordination with local agencies

ICE extends its practical reach through detainers and intergovernmental partnerships: ICE issues immigration detainers or requests to state and local jails and coordinates with local law enforcement during operations, and when local agencies do not honor detainers ICE may pursue “at‑large” arrests in the community—practices the agency defends as public‑safety measures but that critics say raise civil‑liberty and procedural concerns ^{[8] [7]}.

6. Discretion, detention policy and political controversy

ICE’s authority to detain in public is exercised within a framework of administrative discretion and detention-management policy—ICE says it detains to secure presence for proceedings or removal and to address statutory mandatory-detention categories, but critics and news reporting highlight aggressive public arrests, changes in enforcement intensity under different administrations, and proposed legislation to limit ICE actions in “sensitive locations,” underscoring that legal authority is intertwined with policy choices and political debate ^{[9] [10] [1]}.

7. What remains contested or outside the available reporting

While sources agree ICE can arrest in public and use administrative warrants, questions persist—and are litigated—about the precise scope of permissible tactics in borderline contexts (e.g., semi‑private workplace areas, courthouses within certain distances) and about remedies when rights are violated; the provided reporting documents statutory authorities, agency practices and some court constraints but does not resolve every factual nuance of ongoing litigation or post‑2025 policy changes in detail ^{[3] [1] [6]}.