On the campaign trail, President-elect Donald Trump repeatedly vowed to begin “the largest deportation program in American history.” How exactly he plans to carry that out, and how many he ultimately intends to deport, remains unclear.

Although Trump puts the number of immigrants living in the U.S. illegally at more than 20 million (without providing backup), the Pew Research Center estimates the number at 11 million as of mid-2022, based on the latest Census data. Trump has occasionally said that all of them will have to leave and apply to legally get back in. At other times, when pressed about how he will accomplish that, Trump has said he plans to initially target immigrants in the country illegally who have committed crimes and immigrants whose asylum bids were denied by the courts, but who have still not left the country.

“On day one, I will launch the largest deportation program of criminals in American history,” Trump said at a rally in Pennsylvania the day before the election. “We’re going to get them out. We have to. Dwight Eisenhower has the record. … But we’re going to unfortunately beat the record.”