Skip to navigation

Skip to main content

Rural Migration News Blog

contact us

Unauthorized Migration to the US

 Click here to download this blog post as a PDF file

August 18, 2021

The number of unauthorized foreigners in the US peaked at 12.2 million in 2007

Most unauthorized foreigners in the US were born in Mexico. After the 2008-09 recession, a combination of improving conditions in Mexico and stepped up border enforcement discouraged illegal Mexico-US migration and encouraged some unauthorized Mexicans in the US to return to Mexico. Mexicans are still almost half of all unauthorized foreigners, but Central Americans are approaching 20 percent of the unauthorized population.

Mexicans were half of the unauthorized and Central Americans 20 percent in 2017

Mexicans were half of the unauthorized and Central Americans 20 percent in 2017
  2007 2017 Change
U.S. Total 12,200 10,500 -1,750
Latin America
Mexico 6,950 4,950 -2,000
Central America 1,500 1,900 400
South America 900 775 -130
Caribbean 475 475
Other Regions
Asia 1,300 1,4500 130
Europe, Canada 650 500 -150
Middle East 140 130
Africa 250 250

By 2016, two thirds of the unauthorized foreigners had been in the US more than 10 years, compared with less than 40 percent before 2005. Over 80 percent of unauthorized Mexicans were in the US at least a decade in 2017.

2/3 of unauthorized foreigners were in the US at least 10 years in 2016

Mexico. The scale and direction of Mexico-US migration has changed. Between 1995 and 2000, four Mexicans moved to the US for every Mexican who moved from the US to Mexico. Between 2005 and 2014, net Mexico-US migration was negative, meaning that more Mexicans returned to Mexico than moved to the US (net flows include all migration, legal and unauthorized). Between 2014 and 2018, there has once again been more Mexico to US than US to Mexico migration.

Net Mexico-to-US migration rose in recent years

The number of Mexican-born US residents peaked at 12.8 million in 2007 and fell to 11.4 million in 2019.

The number of Mexican-born US residents fell more than 10% after 2007

Beginning in March 2020, the US government used Title 42 of the Public Health Act to return Mexicans and other foreigners who are apprehended just inside the Mexico-US border to Mexico. Some Mexicans who were returned to Mexico tried to re-enter, so that the number of Mexicans who were apprehended rose in 2020 and 2021 as recidivists were encountered; some were apprehended four or five times before eluding the Border Patrol and entering the US.

Mexicans were 63% of southwest border apprehensions in 2020

Unauthorized migration normally declines during the summer months when the deserts are too hot to cross. However, some 188,829 unauthorized foreigners were encountered just inside the Mexico-US border in June 2021, including 178,000 encountered by Border Patrol agents. A third were recidivists, often solo men, who were encountered at least once during the previous 12 months.

There were 1.1 million encounters during the first nine months of FY21, putting the US on track to match or exceed the 1.6 million apprehensions in FY00.

Central Americans detained by the Border Patrol in July 2021


Gonzalez-Barrera, Ana. 2021. Before COVID-19, more Mexicans came to the U.S. than left for Mexico for the first time in years. Pew.

Hugo, Mark. 2021. Key facts about the changing U.S. unauthorized immigrant population. Pew.

Subscribe via Email

Click here to subscribe to Rural Migration News via email.