Resources for the Study of Immigration to the United States

The United States government counts immigrants at two points. One is at the time of entry into the United States. Immigration and Customs Enforcement does this count, and transmits the data to the Department of Homeland Security's Office of Immigration Statistics, which breaks down the data by visa type and various demographic factors. This link should go to the Office of Immigration Statistics page with links to current and historical tables and publications.

The second point at which the federal government counts immigrants is during the Census, which takes place every year ending in a zero. The main purpose of the Census is to count residents in each state and Congressional District for the purpose of redistricting as the population shifts, but since the first Census was taken in 1790, these decennial el events have become treasure troves of data. This link goes to the Census Bureau's main page for the "foreign-born," as the Census designates this population.

Every time the federal government takes a Census, the New York City Department of Planning analyzes the data on the foreign-born that is relevant to the city to be able to anticipate the need for new language services, or for language services to new demographic groups. This is a link to the most recent such publication.

New York City Department of Planning analysis of the 2000 Census, with statistics relevant for the city.

Baruch's statistics aren't as complex as those from the City Planning Department but they're more up to date.

Even naming immigrants without visas is difficult. It isn't a good idea to call them "illegal," because a thorough investigation may establish legal status. Counting those who come without immigration or refugee visas involves mathematical analysis of Census counts of foreign-born and Department of Homeland Security counts of visas issued. The Brookings institute, a think tank interested in immigration as part of a mix of national and world political and economic issues, has a good explanation of the math needed, and the most recent results.

The Center for Migration Studies is interested primarily in immigrants and refugees from a human-rights standpoint, but is respected for the integrity of its data. Its data on unauthorized immigrants is also easy to use, as CMS provides an interactive map that allows researchers to breakdown data by geography and by various demographic factors.

The Pew Research Center is interested in immigrants as part of an overall concern for individual and community welfare. When dealing with contested numbers such as immigration, it's important to get as many estimates as possible from researchers who are interested in the question for different reasons and who use different methodologies to come to their answers.