Estimates of the Unauthorized Immigrant Population Residing in the United States: January 2009
"This report provides estimates of the number of unauthorized immigrants residing in the United States as of January 2009 by period of entry, region and country of origin, state of residence, age, and gender. The estimates were obtained using the “residual” methodology employed for estimates of the unauthorized population in 2008 (see Hoefer, Rytina, and Baker, 2009). The unauthorized resident population is the remainder or “residual” after estimates of the legally resident foreign-born population – legal permanent residents (LPRs), asylees, refugees, and nonimmigrants – are subtracted from estimates of the total foreign-born population. Data to estimate the legally resident population were obtained primarily from the Department of Homeland Security (DHS) while the American Community Survey (ACS) of the U.S. Census Bureau was the source for estimates of the total foreign-born population.

In summary, DHS estimates that the unauthorized immigrant population living in the United States decreased to 10.8 million in January 2009 from 11.6 million in January 2008. Between 2000 and 2009, the unauthorized population grew by 27 percent. Of all unauthorized immigrants living in the United States in 2009, 63 percent entered before 2000, and 62 percent were from Mexico..."