evidence: Different immigration groups, using different methodologies, estimate that the population here illegally ranges from 10.9 million to 16.8 million. Immigration officials have stopped people trying to enter the U.S. illegally 9.5 million times under President Joe Biden’s administration. But that doesn’t mean 9.5 million people are now living in the U.S.; millions were not allowed in. People dying, leaving the U.S. or legalizing their immigration status change the population-here-illegally number.