The U.S. Justice Department on Thursday sued the city of Boston and its leaders, alleging the city’s sanctuary policies violate federal law and interfere with immigration enforcement.
The complaint, filed Sept. 4, 2025, contends that Boston’s refusal to cooperate with federal immigration authorities has resulted in the release of dangerous noncitizens who should have been subject to removal. "The City of Boston and its Mayor have been among the worst sanctuary offenders in America — they explicitly enforce policies designed to undermine law enforcement and protect illegal aliens from justice," said Attorney General Pamela Bondi in a statement announcing the suit. "If Boston won’t protect its citizens from illegal alien crime, this Department of Justice will."
The lawsuit names the city and its senior municipal officials, including Mayor Michelle Wu, and asks a federal court to invalidate policies the Justice Department says impede the federal government’s authority to enforce immigration laws. It follows a pattern of litigation by the Trump administration targeting jurisdictions it labels "sanctuary" cities and counties.
In recent months, the administration has filed similar lawsuits against Los Angeles, New York City, Denver and Rochester, New York, and sued four New Jersey municipalities in May. Those suits generally argue that local policies that limit cooperation with U.S. Immigration and Customs Enforcement conflict with federal statutes and the Supremacy Clause of the Constitution.
The Boston complaint alleges specific instances in which local policy resulted in federal immigration detainers not being honored and ineligible noncitizens being released from custody, though the filing contains the details the department says substantiate its claims. The Justice Department is seeking relief from the court to enjoin the city from continuing policies that it says obstruct federal enforcement.
Boston officials did not immediately respond to requests for comment. City leaders and advocates for immigrant communities have in the past defended sanctuary-style policies as measures that promote public safety by encouraging cooperation with local law enforcement and protecting due process for immigrants.
Legal experts say such cases typically raise questions about federalism, the scope of the federal government’s immigration enforcement authority, and the limits of municipal power to set local public-safety priorities. Courts have in prior cases reached differing conclusions depending on the precise statutes and policies at issue, and litigation of this type has produced a mix of rulings, appeals and settlements.
The suit adds another high-profile legal confrontation between the Trump administration and Democratic-run cities over immigration policy and the balance between federal and local responsibilities for public safety and enforcement. The case will proceed in federal court, where judges will weigh the administration’s challenge to Boston’s policies and consider whether those policies unlawfully obstruct federal immigration efforts.