Who Is an Undocumented Immigrant?

Answers to common questions about illegal immigration in the United States.

The easy definition of an undocumented immigrant is that it’s a foreign-born person who doesn’t have a legal right to be or remain in the United States. But that’s where the easy part stops. Let’s look at some common questions and misconceptions about undocumented immigrants.

Is an undocumented immigrant the same as an illegal alien?

Yes, but “illegal alien” is not a technical term – it’s the popularly used jargon, nowhere found in the U.S. immigration laws. Because of its insulting connotations even though it covers a wide variety of types of people, however, we at Nolo prefer to use the more neutral term, “undocumented immigrant.”

Do all undocumented immigrants sneak across the U.S. border?

Some, but not all. Although accurate numbers are hard to come by, it’s clear that a significant number of undocumented immigrants originally came to the U.S. legally, whether as tourists or on some other nonimmigrant (temporary) visa, and then failed to leave.

Why hasn’t the U.S. deported all undocumented immigrants?

Partly, U.S. enforcement resources are insufficient to keep up with the numbers. According to a 2010 report by the Center for American Progress, it costs $23,480 to deport just one person.

It’s also important to understand, however, that there are some gray areas, where someone who is undocumented has what almost amounts to a right to remain in the United States.

Take, for example, the spouses and children of U.S. lawful permanent residents (green card holders) who have filed a visa petition for them to immigrate. Because of annual limits on visas, these spouses and children may be on a waiting list, with no current right to be in the United States. But some have come to the U.S. anyway, unwilling to be separated from their family, or unclear on the law. And if they are covered by an old law called Section 245(i), they’re better off staying in the U.S. than leaving, because leaving could expose them to a bar on reentry (as described in “Consequences of Unlawful Presence in the U.S. -- Three- and Ten-Year Time Bars”), whereas staying will allow them to "adjust status," or submit their green card application with their local USCIS office. The immigration enforcement authorities deliberately make no effort to remove such family members from the United States.

What's more, under a policy called “prosecutorial discretion,” various immigrants, such as students and those with close family members in the U.S., are supposed to be largely left alone by the immigration authorities, so that the authorities can concentrate on immigrants who are criminals or otherwise a risk to U.S. society. Some of these immigrants may actually be granted a sort of limbo status called "deferred action," and in some cases a work permit. See, for example, Nolo's articles on “Deferred Action for Childhood Arrivals (DACA)” and “How ICE Policy of Prosecutorial Discretion May Help Gay or Lesbian Partners of U.S. Citizens.”

Another gray area is people fleeing persecution, and planning to apply for asylum in the United States. Particularly if they are being sought for persecution by their own government, or unable to make direct contact with a refugee agency, their only choice for U.S. entry may be to come illegally. During the time that they are preparing an application for asylum, they have no actual right to be in the U.S. – but then again, if they are caught and placed in removal proceedings, they are allowed to claim asylum at that point, and may very well be approved for asylum (and one year later, eligible for a green card).

How many undocumented immigrants are in the United States?

Again, that’s hard to say. The Department of Homeland Security (DHS) estimated the number in 2011 at 11.5 million.

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