The American Community Survey (ACS) was launched in 2005 to replace the census long form. It was designed to provide communities with reliable and timely demographic, social, economic, and housing data every year. 

The primary role of the ACS is to help Congress determine funding and make informed policy decisions about a wide variety of federal programs. Information from the survey generates data that help determine how hundreds of billions of dollars in federal and state funds are distributed each year. 

The ACS covers many diverse subjects. It includes survey items relevant to international migration research such as:

• U.S. citizenship status
• Nativity
• Year of naturalization
• Year of entry into the United States
• Residence one year ago
• Race
• Ethnicity
• Ancestry
• Language spoken at home

The ACS is a national, ongoing survey that uses continuous measurement methods, aggregating a series of monthly estimates to produce estimates for census tracts, block groups, cities, metropolitan areas, counties, states, and the nation. Every year, the Census Bureau publishes one-year estimates for geographic areas with populations of 65,000 or more. These larger geographic areas include the nation, all states, District of Columbia, Puerto Rico, and some counties and metropolitan areas. The ACS sample is too small to provide single-year estimates for geographic areas with smaller populations, such as many counties, census tracts, and block groups. For these smaller geographic areas, five years of data are pooled together to create more precise multiyear estimates. 

Estimates are subject to sampling variability. For that reason, ACS data products report estimates with their corresponding margins of error, allowing for the calculation of 90 percent confidence intervals. For an easy way to conduct statistical testing on estimates from the ACS or other Census Bureau surveys, use the Census Bureau’s Statistical Testing Tool.

Due to its large sample size of over 3.5 million households per year, the ACS is a preferred source of data on the foreign-born population for geographies below the national level.

Information on the foreign-born population in the United States based on ACS and Decennial Census Sample data is available through data.census.gov. Instructions and lists of ACS tables by subject and table number can be accessed in the links below.

For a chart of data tools by which to access estimates and microdata from the ACS, click here. Examples include QuickFacts, My Congressional District, and Census Business Builder.

Data users interested in conducting a custom analysis of ACS data can use ACS Public Use Microdata Sample (PUMS) files. These microdata files contain population and housing unit responses collected on individual ACS questionnaires, but for a subsample of ACS housing units and group quarters persons.

To learn more about the ACS, click here. To learn more about the Foreign Born topic, including definitions of terms and popular ACS tables, click here.

Microdata Access on data.census.gov/mdat allows you to create custom tables without having to use your own statistical software or special programming. Instructions for using the site are available on the Microdata Access Resources page

For more information about PUMS, click here.