Just to clarify, make sure we are on the same page, Illegal Immigrant/Alien is a Subset of Foreign Born.

Yes, "illegal aliens" (or more precisely, foreign-born individuals who are present in the United States without lawful immigration status) is a subset of the broader category "foreign-born."

Here’s the breakdown using standard U.S. demographic and legal definitions (primarily from the Census Bureau and DHS):

• Foreign-born (sometimes called “foreign-born population” or “immigrant population” in Census data)
  = Everyone born outside the United States to non-U.S.-citizen parents.
  This includes:

  • Naturalized U.S. citizens
  • Lawful permanent residents (green-card holders)
  • Legal temporary residents (students, H-1B workers, etc.)
  • Refugees and asylees
  • Undocumented/illegal immigrants (“illegal aliens” in legal terminology)

• Illegal aliens / Unauthorized immigrants / Undocumented immigrants
  = The subset of foreign-born people who either:

  • Entered the United States without inspection (e.g., crossed the border illegally), or
  • Entered legally but violated the terms of their admission (e.g., overstayed a tourist or student visa)

So visually:

Foreign-born population
├── Naturalized citizens
├── Lawful permanent residents
├── Legal nonimmigrants (temporary visas)
├── Refugees/asylees
└── Unauthorized/undocumented immigrants ← “Illegal aliens”

Current estimates (as of 2024–2025):

• Total foreign-born in the U.S.: ≈ 48–51 million (≈ 14–15% of the population)
• Unauthorized/undocumented portion: ≈ 11–13 million (roughly 22–26% of the total foreign-born)

Therefore, all illegal aliens are foreign-born, but only a portion (about one-fourth) of the foreign-born population consists of illegal aliens.