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 undocumented immigrant population in the United States is probably about 9 million people. This number had been 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 undocumented immigrant residents, respectively. Between 1990 and 2000, the undocumented 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 are Mexico, El Salvador, Guatemala, Colombia, and Honduras. The largest source country for unauthorized immigrants in 2000 was Mexico. According to the INS, the unauthorized immigrant population from Mexico was estimated to be 4.8 million in 2000, or 69 percent of the total unauthorized resident population. High populations (over 100,000 unauthorized immigrant residents in the United States) also came from China and Ecuador.