Foreign-born population share, explained

What it measures

The foreign-born share is the percentage of the total population that was born outside the United States. The numerator includes naturalized US citizens, lawful permanent residents (green card holders), and other people born abroad regardless of immigration status. People born in US territories (Puerto Rico, Guam, US Virgin Islands, American Samoa, Northern Mariana Islands) are NOT counted as foreign-born, they are US-born by definition. People born abroad to a US citizen parent are also not counted as foreign-born.

The metric does not distinguish by visa status, country of origin, or year of arrival; those breakdowns are published in companion tables (B05002, B05003, B05004, B05005, etc.).

Why it matters

Foreign-born share is one of the most-tracked demographic metrics in US data because it has direct implications for labor markets, language services, school enrollment, healthcare delivery, and political representation. Metros with high foreign-born shares typically also have larger labor-force participation in specific industries (construction, food service, agriculture, technology, healthcare), more children in dual-language education programs, and more demand for naturalization and immigration services. The metric is also the foundation for understanding the demographic momentum of any metro, without continued immigration, much of the US would be experiencing population decline.

How the Census measures it

ACS Table B05002, Place of Birth by Nativity and Citizenship Status. The foreign-born population is the count of people born outside the US, Puerto Rico, and other US territories, less those born abroad of American parents. CensusEasy divides by the total population to compute the share.

How to read the numbers

The US foreign-born share is about 14%. State rates range from about 2% (West Virginia, Mississippi) to over 25% (California, New York, New Jersey, Florida). Among metros, the leaders (Miami, San Jose, Los Angeles, San Francisco, New York) all exceed 30%; Miami exceeds 50%. The lowest figures are in the rural South, the rural Plains, and parts of Appalachia where immigration has been minimal for generations. A foreign-born share above 20% in a metro typically indicates a diversified economy with several major employer sectors plus a strong family-reunification immigration base.

Caveats and limitations

The metric counts the total foreign-born population, not just recent arrivals, naturalized citizens who immigrated 40 years ago are counted the same as people who arrived last year. For metros where the timing of immigration matters (in housing markets, for example), the "entered the US in the past 10 years" breakdown is more informative. The metric also doesn't distinguish by documentation status; published estimates of the unauthorized population come from different methodologies.