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New national and state estimates of America's unauthorized immigrant population released

Minnesota’s statistics mirror the nation

February 15, 2013

Media note: The authors will be in New York for the release of this research on Friday, Feb. 15. They are available for interviews via phone after 11am Central time.  

The number of unauthorized immigrants arriving in the U.S. peaked at more than one million annually between 1999 and 2001, and then declined rapidly thereafter, found a study co-authored by U of M Sociology professor John Robert Warren and released today in the peer-reviewed journal International Migration Review (IMR). 

However, because the number of unauthorized immigrants leaving the country has risen steadily over time, in 2008 and 2009 the U.S. actually lost more unauthorized immigrants than it gained

The report, titled "Unauthorized Immigration to the United States: Annual Estimates and Components of Change, by State, 1990 to 2010," provides new state and national estimates of the total size of the unauthorized immigrant population through January 2010. The study’s lead author is Robert Warren, formerly of the U.S. Immigration and Naturalization Service (INS).

"One unique feature of our estimates is that we can also describe the numbers of unauthorized immigrants entering and leaving the population each year," noted the U of M’s Warren. "Another is that we produce reliable annual estimates for each state as well as for the country as a whole."

The authors estimate that about 100,000 unauthorized immigrants lived in Minnesota in 2010.  Like the country as a whole, the number of unauthorized immigrants entering Minnesota has declined after peaking between 1999 and 2001.  Because the number of unauthorized immigrants leaving Minnesota has grown steadily over time, the state’s total population of unauthorized immigrants fell in 2008 and 2009.  In 2009, for example, the report estimates that about 5,000 unauthorized immigrants came to Minnesota while about 7,000 left (mainly via removal by the Department of Homeland Security and through voluntary emigration). 

The authors also find that:

  • The total number of unauthorized immigrants in the United States was about 11.7 million in January 2010, about 4 million higher than it was in 2000.
  • However, the United States lost more unauthorized immigrants than it gained in both 2008 and 2009.
  • In January 2010, nearly 3 million unauthorized immigrants --- about 25 percent of the nation’s total --- resided in California. Near two-thirds of all unauthorized immigrants lived in just seven states: California, Texas, Florida, New York, Illinois, New Jersey, and Georgia.
  • Between 2000 and 2009, inflows declined in every state except Mississippi (and Washington, D.C.), and outflows increased in every state. As a result, 29 states and D.C. experienced net losses in their populations of unauthorized immigrants in 2009.
  • The seven states with the fastest growing populations of unauthorized immigrants over the past two decades, in declining order, were in the southeast: Alabama, South Carolina, North Carolina, Tennessee, Arkansas, Kentucky, and Georgia. In each of these states, the unauthorized immigrant population was more than 11 times larger in 2010 than it was in 1990.

"The study represents the most comprehensive analysis of the U.S. unauthorized population to date," said Ellen Percy Kraly, editor of IMR and professor of geography at Colgate University. "It highlights the dynamic nature of the unauthorized population, particularly the role of departures, and uniquely provides trends – annual estimates over two decades – for each state. This research also anticipates the critical contribution of demographic analysis to U.S. immigration policy evaluation and development."

The full study is available at

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