Illinois

Definitions

• The term "foreign born" refers to people residing in the United States at the time of the population survey who were not U.S. citizens at birth. The foreign-born population includes naturalized U.S. citizens, lawful permanent immigrants (or green-card holders), refugees and asylees, certain legal nonimmigrants (including those on student, work, or some other temporary visas), and persons residing in the country without authorization.
• The term "U.S. born" refers to people residing in the United States who were U.S. citizens in one of three categories: people born in one of the 50 states or the District of Columbia; people born in U.S. Insular Areas such as Puerto Rico or Guam; or people who were born abroad to at least one U.S. citizen parent.
• The term "low-income families" refers to families with annual incomes below 200 percent of the federal poverty threshold.

Data-related notes

• The letter N indicates that an estimate could not be provided by the Census Bureau because the number of sample cases was too small for this state.
• Race and Hispanic origin: The Census Bureau made some improvements and changes in how respondents were asked about their race and Hispanic origin on the 2020 decennial Census form. The goal was to achieve a more accurate portrait of how U.S. residents self-identify. The same changes were implemented in the subsequent ACS as well. Note that the racial composition of the U.S. population in the 2021 ACS looks different from prior ACS years. For instance, the proportion reporting “two or more races” has increased, while the proportion of “white alone” decreased, reflecting both the growth of a more racially diverse population and the changes in questionnaire design. Race and Hispanic origin comparisons between the 2021 ACS and earlier ACS years or pre-2020 decennial Censuses should be made with caution. For more details, visit the Census Bureau’s Resource Library.
• For “Median Age” and “Household Size”: Data for Alaska, Maine, Mississippi, Montana, North Dakota, South Dakota, Vermont, West Virginia, and Wyoming are from the U.S. Census Bureau's pooled 2017-2021 American Community Survey (ACS). Data for the United States overall and for the remaining states are from the 2021 ACS.
• Region of birth: For 1990, 2000, and current ACS year, the total for the region of birth of the foreign born is different from the total foreign born. This is because the 1990 total excludes those who did not report a country of birth and those born at sea, while the 2000 census and the current ACS year totals exclude those born at sea.
• Countries of birth: These are the largest countries of birth reported by the Census Bureau. Some countries are only listed as part of a larger geographic region. For example, those born in Somalia are included only among those born in Eastern Africa. Therefore, a few states may have larger populations of foreign-born persons born in countries not listed individually in census data. For each of the three years, countries of birth reflect geographic boundaries as of that year.
• Children: The data here include children between ages 0 and 17 (regardless of their nativity) who reside with at least one parent. This means that the number of children shown here is smaller than the overall number of U.S. children under 18. Since 2013, the U.S. Census Bureau has included children of same-sex married couples in its count of children in families and subfamilies.