A new report from the Center for Immigration Studies uses data from the 1990 and 2000 Censes and 2010-2014 the American Community Survey (ACS) to show how the adult immigrant population (illegal and legal) has grown from 1990 to 2014 at the county level. The analysis shows that in 232 U.S. counties the number of adult immigrants has quadrupled in 14 years.

Other key findings of the study include:

  • The number of counties where immigrants made up at least 20% of the adult population jumped from 44 counties in 1990 to 152 in 2014.
  • In 1990, 1 in 8 Americans lived in a county where at least 20%of adults were immigrants. By 2014, 1 in 3 people did.
  • While the immigrant share of adults has often increased the most in counties with smaller populations, growth since 1990 has also been dramatic in many large counties with over a million residents. 

The analysis focuses strictly on adult immigrants (18 or older) because as workers and potential voters they have the most immediate impact on a community.

Steve Camarota director of research at CIS, said the reasons why the immigrant population is exploding vary county by county. In some cases, he said, jobs lure newcomers, who come both legally and illegally. In others, legal immigrants arrange to bring their relatives to the United States. Once a county reaches a critical mass of immigrants, people from the home country start to seek it out when they arrive, he said.

Read the full report at

Legal Immigration
Illegal Immigration

Updated: Wed, Oct 11th 2017 @ 3:49pm EDT