Office of Immigration Statistics POLICY DIRECTORATE Estimates of the Unauthorized Immigrant Population Residing in

This report provides estimates of the size of the unauthorized immigrant population residing in the United States as of January 2011 by period of entry, region and country of origin, state of residence, age, and sex. The estimates were obtained using the “residual ” methodology employed for previous estimates of the unauthorized population (see Hoefer, Rytina, and Baker, 2011). The unauthorized immigrant population is the remainder or “residual ” after the legally resident foreign-born population—legal permanent residents (LPRs), naturalized citizens, asylees, refugees, and nonimmigrants—is subtracted from the total foreign-born population. Data to estimate the legally resident population were obtained primarily from the Department of Homeland Security (DHS), whereas the American Community Survey (ACS) of the U.S. Census Bureau was the source for estimates of the total foreign-born population. The 2011 unauthorized estimates should not be com-pared with DHS estimates previously released for 2005–2010. Updates to population estimates used to weight the ACS had a substantial impact on changes in estimates of the foreign-born population betwee