what was said

“Illegal immigration costs our country hundreds of billions of dollars.”

the facts

This is disputed.

Mr. Trump is most likely referring to an estimate from an anti-immigration group that has been heavily criticized by other researchers for its methodological flaws.

The group, the Federation for American Immigration Reform, estimated in 2017 that illegal immigration costs the United States $116 billion each year in spending on education, health care and law enforcement.

The Cato Institute, a libertarian think tank, found that the $116 billion estimate overcounted welfare benefits that undocumented immigrants receive, and undercounted the taxes that they pay. It said the $116 billion estimate would be more accurately accounted as ranging from $3.3 billion to $15.6 billion if those costs were considered.

Additionally, the American Immigration Council studied an earlier but similar estimate by the Federation for American Immigration Reform. It concluded that education and health care account for more than half of the costs, and that the benefits were afforded to many American-citizen children of undocumented immigrants.