The ACS asks each respondent to write their ancestry or ethnic origin, and records up to two ancestries per person (the first two ancestries written by the respondent).
Ancestry does not necessarily equate with place of birth, as a person can be generations removed from the ancestors they choose to identify with. Some respondents also write “American” as their ancestry for various reasons, whether their ancestors have been in the United States for a long time or they are foreign born but consider themselves part of American society.
The table for People Reporting Single Ancestry (B04004) shows data for those who reported only one ancestry, while People Reporting Multiple Ancestry (B04005) shows data for those who reported more than one ancestry. People Reporting Ancestry (B04006) shows data for those who reported any ancestry, regardless of whether it was the only ancestry or part of multiple ancestries they reported.
Note: this means that values in B04005 and B04006 will not necessarily add up to match totals, because one person may be represented under more than one ancestry.
This information is often used to enforce nondiscrimination and equal opportunity laws.
Note: Separately from the ancestry question, Census allows people to specify their race with detailed answers which can be the same as answers for ancestry. See our Race and Hispanic Origin page for some more information. At this time, we can't make a recommendation about when to use each table. Some discussion of the two questions can be found in the Pew Research Center's 2015 report, "Multiracial in America"
|People Reporting Single Ancestry
|People Reporting Multiple Ancestry
|People Reporting Ancestry
|‡Table also available in "collapsed" version: change "B" to "C" for table code.