Former ICE Director Tom Homan to join Trump administration as 'border czar'

Former Immigration and Customs Enforcement Director Tom Homan is going to be the "border czar" in the Trump administration, President-elect Donald Trump announced on Truth Social.

Homan, a staunch Trump supporter, will be in charge of the mass deportations that have been promised by Trump throughout his 2024 campaign.

"I've known Tom for a long time, and there is nobody better at policing and controlling our Borders," Trump wrote in his post on Sunday evening.

"Likewise, Tom Homan will be in charge of all Deportation of Illegal Aliens back to their Country of Origin. Congratulations to Tom. I have no doubt he will do a fantastic, and long awaited for, job," Trump added.

Homan oversaw ICE during the Trump administration's "zero tolerance" enforcement that separated parents from their children at the border.

The American Civil Liberties Union (ACLU) estimates there are anywhere from 500 to 1,000 families who have not been reunited.

In August, ACLU attorney Lee Gelernt told ABC News it's impossible to know an exact number because they haven't found all of them.

During an interview on "60 Minutes" in October, Homan said that future family separations need to be considered, but also said, "families can be deported together."

With immigration a top issue for voters, Trump has said he's determined to round up and deport millions of migrants living in the U.S. without legal permission.

He reiterated a campaign promise to enact mass deportations on "Day 1" during his rally at Madison Square Garden in New York City in October.

"On Day 1, I will launch the largest deportation program in American history to get the criminals out," he said. "I will rescue every city and town that has been invaded and conquered, and we will put these vicious and bloodthirsty criminals in jail, then kick them the hell out of our country as fast as possible."

To do so, the former president said he would use local law enforcement and the National Guard to find migrants living across the U.S.

Trump has railed against the Biden administration's immigration policies, in part claiming they have made America less safe, though statistics show that U.S.-born citizens are more than twice as likely to be arrested for violent crimes than undocumented immigrants.

An estimated 11 million people are living in this country without legal immigration status.

If feasible, the cost to deport even 1 million undocumented immigrants a year would cost over $88 billion, for a total of $967.9 billion over more than 10 years, according to a report from the American Immigration Council.

ABC News' Armando Tonatiuh Torres-García and Meredith Deliso contributed to this report.