Unauthorized Immigration to the United States

This fact sheet provides an estimate and brief description of the unauthorized immigrant population in the United States in 2003.

The size of the unauthorized immigrant population in the United States was probably about 9 million people in 2003, a number growing on average by about 350,000 people per year between 1990 and 1999. In 2003, California and Texas were the states with the largest unauthorized populations, with an estimated 2.2 million and 1 million unauthorized immigrant residents, respectively. Between 1990 and 2000, this population grew fastest in California, Texas, Illinois, Arizona, Georgia, North Carolina, and New York, in that order.  

The five countries of origin with the largest unauthorized immigrant populations were Mexico, El Salvador, Guatemala, Colombia, and Honduras. Mexico was by far the largest source country, with a population estimated by the U.S. government at 4.8 million in 2000, or 69 percent of the total unauthorized resident population.