What is an Alien Registration Number and Where Can I Find It?

The “alien registration number” or “A-Number” can be critical for tracing your file through the U.S. immigration system. Learn more about what an A-number is, who gets one, and where to look if you’ve lost your A-number.

By , J.D.

Many types of U.S. immigration application forms ask for the foreign-born person's "alien registration number" or "A-number." It is often key to tracing one's file through the U.S. immigration system.

Confusingly, however, not everyone who interacts with the U.S. immigration bureaucracy receives an A-number. This article will review what an A-number is, who gets one, and where to look if you're not sure whether you have one or what number was assigned to you.

What Is an Alien Registration Number (A-Number)?

Literally speaking, an A-number is an eight- or nine-digit number associated with someone's U.S. immigration file. (The more recent ones have nine digits.)

It's also sometimes called a "USCIS #," in particular when it appears on a lawful permanent resident card (a green card) or an Employment Authorization Document (an EAD or work permit).

The A-number is meant to help U.S. immigration agencies keep track of foreign nationals using something more unique than their names (duplicates are common!) and to keep the information on each immigrant all in one file. These various agencies include the Department of Homeland Security (DHS), including its sub-agencies U.S. Citizenship and Immigration Services (USCIS), Immigration and Customs Enforcement (ICE), U.S. Customs and Border Protection (CBP). The U.S. Department of State (DOS) also has a role in handling immigration applications for visas, and shares information with these other departments, along with the National Visa Center (NVC).

Who Receives an A-Number?

The main circumstances in which a foreign-born person receives an A-number are:

In most cases, particularly if you are granted U.S. permanent residence, the A-Number you're assigned will be your one and only A-Number for life. There are exceptions, however, when a foreign national receives more than one A-Number. It's usually because U.S. immigration authorities for some reason opened more than one file on the person.

Which Foreign Citizens Don't Receive an A-Number?

Temporary visa holders or entrants to the U.S. (technically often known as nonimmigrants) will not normally be given A-Numbers as part of their status or paperwork. However, they might end up receiving an A-Number while they're in the United States, perhaps if they apply for an EAD or some other immigration benefit.

This occurs especially often with foreign students on F-1 visas, who aren't normally allowed to work in the United States except on campus, but who can apply for work permits in certain circumstances.

What Other Numbers Might an Immigrant Mistakenly Confuse With an A-Number?

The A-number isn't the only one someone might see associated with an immigration application. Be sure not to confuse it with, for example:

  • A USCIS receipt number. This is issued by the USCIS service center to which you (or your family or employer petitioner) sent an application. It will appear on the I-797 receipt notice you or your petitioner gets from USCIS, usually in the upper left corner. It's got three letters and ten numbers. The letters are abbreviations indicating which service center is handling the application, such as EAC, WAC, LIN, SRC, NBC, MSC, or IOE. The numbers are a combination of the date your case was first opened and a case number assigned to you. Your USCIS receipt number is useful for checking your application status, but isn't particularly relevant beyond that one application.
  • An I-94 number. CBP assigns an 11-digit I-94 number to every nonimmigrant (temporary visitor) who enters the United States at a border or other port of entry (such as an airport or seaport), at the same time as it sets their required departure date. In the past, these were given out solely as small paper cards, but now in most cases they're kept as records on the CBP website. These I-94 numbers are also assigned by USCIS to people adjusting status (obtaining a green card) while in the U.S., as well as to people who've been approved for asylum or are visa holders extending their permitted U.S. stay.
  • A USCIS Online Account Number. This is a 12-digit number USCIS gives to immigrants who register to communicate with the agency online. Think of it more as an access number than a personal identification number. Not everyone has one. You might notice, however, that various USCIS applications ask for the online account number, if you have one.

All these numbers are important and worth keeping track of. The U.S. immigration system is a huge bureaucracy, and numbers become crucial to organizing files and serving applicants. Most immigration applications ask for every sort of number that's been assigned to you.

What Is an Alien Registration Card?

U.S. lawful permanent residents receive a photo identity card that's often called a green card—and shows their A-number, currently listed as a "USCIS#." More formal names for this include the Permanent Resident Card or Form I-551. U.S. Citizenship and Immigration Services (USCIS) issues green cards to permanent residents as evidence of their lawful status in the United States.

People who are approved for residency at a U.S. consulate first receive an immigrant visa. Only after entering the United States does USCIS prepare and mail them their actual green card.

This doesn't mean that everyone with an A-number receives an Alien Registration Card. To emphasize, only green card holders receive such a card—though other types of cards might show their Alien Registration Number.

Where Do I Find My Alien Registration Number?

Finding your A-number shouldn't be difficult. If you have one, USCIS will list it in any correspondence with you and ask you for it so many times that you should be able to find it on any immigration form you've filled out.

It's also prominently displayed on the front of the green card and employment authorization document (EAD).

If you really can't find your number anywhere, for example if you've lost all your application paperwork and documents, one possibility is to submit what's called a "Freedom of Information Act" or "FOIA" request to the DHS, asking for a copy of your immigration file. See How to Get a Copy of Your Immigration File (FOIA Requests). The catch is, if you have a common name, DHS might have trouble locating your file without your A-Number!

Do I Need an Attorney?

If you're still uncertain about how to deal with U.S. immigration questions such as whether you have an A-Number and if so what it is, consider hiring an experienced U.S. immigration attorney. Nolo's Lawyer Directory offers an easy-to-use online list of lawyers, organized by location and area of expertise, with comprehensive profiles of each one.

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