Race and ethnicity in the United States census

In the United States census, the U.S. Census Bureau and the Office of Management and Budget (OMB) define a set of self-identified categories of race and ethnicity chosen by residents, with which they most closely identify. Residents can indicate their origins alongside their race, and are asked specifically whether they are of Hispanic or Latino origin in a separate question.

Race and ethnicity are considered separate and distinct identities, with a person's origins considered in the census. Racial categories in the United States represent a social-political construct for the race or races that respondents consider themselves to be and, "generally reflect a social definition of race recognized in this country". The OMB defines the concept of race as outlined for the census to be not "scientific or anthropological", and takes into account "social and cultural characteristics as well as ancestry", using "appropriate scientific methodologies" that are not "primarily biological or genetic in reference." The race categories include both racial and national-origin groups.

From the first United States Census in 1790 to the 1960 Census, the government's census enumerators chose a person's race. Racial categories changed over time, with different groups being added and removed with each census. Since the 1970 Census, Americans provide their own racial self-identification. This change was due to the reforms brought about by the Civil Rights Act of 1964 and the Voting Rights Act of 1965, which required more accurate census data. Since the 1980 Census, in addition to their race or races, all respondents are categorized by membership in one of two ethnic categories, which are "Hispanic or Latino" and "Not Hispanic or Latino." This practice of separating "race" and "ethnicity" as different categories has been criticized both by the American Anthropological Association and members of US Commission on Civil Rights.

Since the 2000 Census, Americans have been able to identify as more than one race. In 1997, the OMB issued a Federal Register notice regarding revisions to the standards for the classification of federal data on race and ethnicity. The OMB developed race and ethnic standards in order to provide "consistent data on race and ethnicity throughout the federal government". The development of the data standards stem in large measure from new responsibilities to enforce civil rights laws. Among the changes, The OMB issued the instruction to "mark one or more races" after noting evidence of increasing numbers of mixed-race children and wanting to record diversity in a measurable way after having received requests by people who wanted to be able to acknowledge theirs and their children's full ancestry, rather than identifying with only one group. Prior to this decision, the census and other government data collections asked people to report singular races.

As of 2023, the OMB built on the 1997 guidelines and suggested the addition of a Middle Eastern or North African (MENA) racial category and considered combining racial and ethnic categories into one question. In March 2024, the Office of Management and Budget published revisions to Statistical Policy Directive No. 15: Standards for Maintaining, Collecting, and Presenting Federal Data on Race and Ethnicity that included a combined question and a MENA category, while also collecting additional detail to enable data disaggregation.