President-elect Donald Trump has promised a mass deportation of illegal immigrants once he takes office, and while many people are over-selling what he will be able to achieve, the picture his open-borders opponents are painting of an illegal immigrant-free United States is just not as dire as they think.

Estimates on the size of the illegal immigrant population in the U.S. are just that: estimates. No one has a firm count of how many illegal immigrants there are in the country. The open-borders Migration Policy Institute estimates there are 11 million. The conservative Center for Immigration Studies puts the number closer to 14 million. The Trump campaign says 20 million. The truth is somewhere in between.