About the Data

A project by the Center for Migration Studies of New York (CMS) led to the development of these estimates on the size and characteristics of the undocumented population in the United States at the national and state levels. The purpose of this project is to make the information directly available to a wide cross-section of users.

Methods for Estimates of the Undocumented Population

To derive the estimates, a series of statistical procedures were developed based on microdata collected by the US Census Bureau’s American Community Survey (ACS). The ACS is an annual statistical survey covering approximately one percent of the total US population. The survey provides detailed social and economic data for all states, as well as all cities, counties, metropolitan areas, and population groups of 100,000 people or more.

The methodology involved three major steps:

  1. Applying a series of “logical edits” to identify and remove as many legal residents as possible from the ACS data for non-citizens who arrived after 1981;
  2. Deriving separate population controls, for 145 countries or areas, for Undocumented residents surveyed in the 2010 ACS; and
  3. Using those population controls to select records in the ACS micro-data (public use microdata sample (PUMS)) to be classified as undocumented residents. A final set of adjustments was made to account for undercount in the ACS.

The term “logical edit” refers to the process of determining probable legal status by examining survey data. Respondents were assigned to the legal resident category if they worked in occupations that generally require legal status, were legal temporary migrants, were immediate relatives of US citizens, received public benefits, were from countries where most arrivals would be refugees, or were age 60 or older at entry.

A detailed description of the project and the methodology is available at: Robert Warren, 2021 “In 2019, the US Undocumented Population Continued a Decade-Long Decline and the Foreign-Born Population Neared Zero Growth.” Journal on Migration and Human Security. DOI: https://journals.sagepub.com/doi/10.1177/2331502421993746.

Read more: http://cmsny.org/cms-research/democratizingdata/

Using the Tool

The State and National Data Tool provides data for selected states within the US. To obtain the national estimates, do not click on any state. To obtain state estimates, click on the specific state or states. If you select multiple states, the tool will aggregate those states (sum them together), so that you can use the tool to regionalize. For example, you can select all states that share a border with Canada or Mexico. Remember to scroll down to view all results.

Saving Your Data

To save your data, click on the 'Save as .CSV' button located at the bottom right of the map to download a file of the currently displayed data.

Attribution

Published by the Center for Migration Studies, all rights reserved.
Based on the augmented American Community Survey based IPUMS (Integrated Public Use Microdata Series).
Web tool developed and maintained by the U-Spatial at the University of Minnesota.