No one in ICE detention is being held as punishment for a crime, a distinction often overlooked in discussions of immigrants’ conditions of confinement, advocates say.
Immigration detention is civil detention, not criminal, as the immigration court system is an administrative process, overseen by the U.S. Department of Justice.
That makes the inhumane and overcrowded conditions of detention in U.S. Immigration and Customs Enforcement facilities all the more indefensible, advocates say.
Historically, immigration detention was used rarely, only to hold people who were considered dangerous or a flight risk during the duration of their immigration proceedings, said Nancy Hiemstra and Deirdre Conlon, authors of "Immigration Detention Inc.: The Big Business of Locking Up Migrants."
The use of detention, and profits from its expansion, have exploded since the 1990s as private, for-profit companies — like CoreCivic, which owns and operates Eloy Detention Center in Arizona — have gotten involved in the industry.
Nearly 90% of ICE detainees are held in facilities run by for-profit companies, according to the nonpartisan Migration Policy Institute.
"They get paid with our tax dollars, and they get paid per person, per bed," Phoenix immigration attorney Ravi Arora said. "They’re just literally funneling our tax dollars into their pockets."
The use of mandatory detention has soared to new heights under the second Trump administration, whose 2025 policy to nearly universally detain immigrants facing deportation has been rejected by hundreds of federal judges in legal challenges.
ICE now holds a record 71,000 people in ICE detention, up from about 40,000 when Trump took office in 2025.
About 74% of those in detention have never been convicted of a crime, ICE data show. Of those with convictions, most are for non-violent crimes, such as traffic or immigration violations. (Detainees with prior criminal convictions would have already served their time in the criminal justice system before being picked up by ICE.)
Recently arrived migrants who enter the country without inspection have long been subject to mandatory detention, under the "draconian" set of immigration laws passed in 1996, during the Clinton administration, Arora said.
But DHS, including ICE, always has the discretion to release detainees — either after they arrive at the border, or once they’re already in ICE detention — through its statutory parole authority.
Until now, "every president has used parole authority to release non-dangerous immigrants who arrived at border, after they were screened and vetted," Arora said. "This new push to detain everyone is brand new."
Not only has Trump's DHS completely stopped using its parole discretion, but it’s also expanded the definition of who is subject to mandatory detention to include unauthorized immigrants who have lived in the U.S. for decades.
Funding approved in the "One Big Beautiful Bill" is fueling immigrant detention at a scale never seen before, funneling $45 billion to expanding ICE detention capacity through 2029, even as DHS works to restrict Congressional and internal oversight of the facilities.
In the last month alone, DHS has spent more than $500 million buying up land and warehouses to expand detention capacity, and will need to spend billions more to convert the warehouses, Aaron Reichlin-Melnick, senior fellow at the American Immigration Council, said in a post on X.
"If these mega-camps are utilized to the full capacity ICE intends, they'll be the largest prisons in the country, with little to no real oversight," he wrote.
The DHS buying spree includes the Jan. 23 purchase of land with a 418,000-square-foot warehouse in Surprise, Arizona, for $70 million, The Arizona Republic reported. Rockefeller Group was the seller.
DHS wields the threat of an extended detention in harsh conditions to pressure detained immigrants to stop fighting their cases and take a voluntary departure, immigrant-rights advocates say.
"Rather than focusing on serious public safety threats and flight risks, the Trump administration is primarily using detention to pressure people into giving up their chance to remain in the United States," the American Immigration Council report said.
