Colorado sues Trump administration in effort to block new ICE detention center from opening

Seth Klamann, The Denver Post on Sep 29, 2026

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DENVER — Colorado’s attorney general has joined a flurry of lawsuits challenging the Trump administration’s plans to open a nearly 1,200-bed immigrant detention center northeast of Denver.

Attorney General Phil Weiser‘s office filed the latest suit in federal court on Tuesday, alleging that the Department of Homeland Security and U.S. Immigration and Customs Enforcement violated environmental, immigration and procedural laws when it contracted with the Geo Group to open and operate the state’s second full ICE detention facility in Hudson, roughly 30 miles from Denver.

The state’s lawsuit alleges that the federal government didn’t undertake environmental, infrastructure, or health and safety reviews under the National Environmental Policy Act before giving Geo the green light. It will turn a long-shuttered private prison into what’s now been dubbed the Big Horn Facility.

Among other concerns, the suit alleges that there’s a deer corridor within a half-mile of the prison and that the nearby Box Elder Creek is a designated “aquatic naive species conservation” area.

“We’re now asking the court to cancel the federal government’s contract with the Geo Group that would enable the renovation and operation of this facility in violation of the law,” Weiser said during a news conference Tuesday morning. “And because of the immediate threat of irreparable environmental harms from this pending construction and renovation effort — and from the operation of the facility — we’re asking the court to issue a preliminary injunction that will stop any of this work, and it will prevent this facility from being moved into it.”

The lawsuit is the third filed in recent months that attempts to block the new facility.

Shortly after Geo Group announced it had secured the $528.6 million contract in July, a Weld County resident and a nonprofit group sued the town of Hudson and its leaders, arguing they had to enforce their own development code.

Last week, GreenLatinos and the Colorado Immigrant Rights Coalition filed a separate federal lawsuit against the Trump administration. Like Weiser’s suit, it alleged that the Geo contract violated NEPA.

In an unsigned statement Tuesday, a representative for the Homeland Security Department said the lawsuit was not about the environment but about stopping Trump’s public safety agenda.

Weiser said construction and renovation of the prison, which closed in 2013, had already begun. If the facility does open, it would nearly double Colorado’s immigrant detention capacity amid President Donald Trump’s push for mass deportations.

In addition to a constellation of small, temporary holding rooms, the state has only one immigrant detention center currently. That facility, which is located in Aurora, is also operated by Geo and has a maximum capacity of 1,532.

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