An A-Number, short for Alien Registration Number, is the unique seven-, eight-, or nine-digit code that the Department of Homeland Security assigns to a noncitizen’s immigration file, and you can find it on your Green Card, Employment Authorization Document, immigrant visa foil, USCIS notices, and Certificate of Naturalization.1U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number The number is permanent. It stays with you across every status change and every agency that touches your case, so you’ll need it for almost any form you file or status check you run.
Who Has an A-Number
Lawful permanent residents are the most familiar group. When USCIS issues a Green Card (Form I-551), the A-Number printed on it becomes the identifier for every future filing, from a card renewal to a naturalization application.2U.S. Citizenship and Immigration Services. 13.1 List A Documents That Establish Identity and Employment Authorization Holders of an Employment Authorization Document (Form I-766) also have one, since the number links their work permission back to the same file.3U.S. Citizenship and Immigration Services. Employment Authorization Document
You don’t have to be a permanent resident or work-permit holder, though. DHS assigns an A-Number to anyone placed in removal or deportation proceedings so immigration courts can track the case, and to applicants who file for an immigrant visa, asylum, or another benefit through USCIS, whether or not the application is ultimately approved.
Where the A-Number Appears on Your Documents
Green Card (Form I-551)
On cards issued after May 10, 2010, the number is printed on the front under the label “USCIS Number” or “USCIS#/A-Number.”4U.S. Citizenship and Immigration Services. USCIS Number Cards issued starting May 1, 2017, carry a second copy on the back.2U.S. Citizenship and Immigration Services. 13.1 List A Documents That Establish Identity and Employment Authorization Older cards that predate the redesign still show the number, though the label may differ.
Employment Authorization Document (Form I-766)
The number appears on the front of your EAD, typically under the “USCIS#” heading.2U.S. Citizenship and Immigration Services. 13.1 List A Documents That Establish Identity and Employment Authorization
Immigrant Visa Foil in Your Passport
If you entered on an immigrant visa, the A-Number is printed on the visa stamp inside your passport and labeled “Registration Number.”5U.S. Citizenship and Immigration Services. Immigrant Fee Payment: Tips on Finding Your A-Number and DOS Case ID
Notice of Action (Form I-797)
Any receipt or approval notice USCIS sends for a petition or application generally displays the A-Number near the top, labeled “Alien Number” or “A-Number.”6U.S. Citizenship and Immigration Services. Form I-797 Types and Functions
Certificate of Naturalization (Form N-550)
The A-Number follows you even after you become a citizen. It’s printed on the Certificate of Naturalization as the USCIS registration number, and it’s the number to reference if you ever need to prove your naturalization or request a replacement certificate.7U.S. Citizenship and Immigration Services. Chapter 3 – Certificate of Naturalization
Format and Leading Zeros
An A-Number is always the letter “A” followed by digits. Older files may contain only seven or eight, but current USCIS forms provide nine spaces.1U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number If yours is shorter than nine digits, add zeros after the “A” and before the first digit until every space is filled. “A12345678” becomes “A012345678.”5U.S. Citizenship and Immigration Services. Immigrant Fee Payment: Tips on Finding Your A-Number and DOS Case ID Getting this wrong is one of the fastest ways to trigger a processing delay, so check before submitting.
Does an A-Number Ever Change or Expire
No. Once DHS assigns the number, it stays with you through every status change: from a work permit to a Green Card, and from a Green Card through naturalization.1U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number Physical documents like Green Cards and EADs expire and need renewal, but the underlying number never changes and never expires.
How the A-Number Differs From Other Numbers on Your Paperwork
Several government-issued numbers show up in immigration and tax paperwork, and mixing them up will get a form rejected.
A-Number vs. Social Security Number
A Social Security number is issued by the Social Security Administration, not DHS, and its purpose is wage reporting and tracking eligibility for Social Security benefits.8Social Security Administration. Social Security Numbers for Noncitizens Generally, only noncitizens authorized to work can get one. An A-Number is assigned to anyone with an immigration file, regardless of work authorization. You may eventually hold both, but they belong to separate systems.
A-Number vs. ITIN
An Individual Taxpayer Identification Number is a nine-digit number the IRS issues strictly for federal tax filing. It doesn’t grant work authorization, change immigration status, or identify you outside the tax system.9Internal Revenue Service. Individual Taxpayer Identification Number (ITIN) It has no connection to your immigration file and is not interchangeable with an A-Number on any USCIS form.
A-Number vs. Receipt Number
When USCIS accepts a petition or application, it assigns a receipt number (sometimes called a case number) that starts with three letters followed by digits. That number tracks the specific filing, not the person. You can accumulate many receipt numbers over the years but will only ever have one A-Number. Entering a receipt number where a form asks for the A-Number will cause a rejection.
How to Recover a Lost A-Number
Start by checking every immigration document you still have. The number appears on Green Cards, EADs, visa stamps, I-797 notices, and naturalization certificates, so an old approval notice from a previous application may carry it. People often forget an I-797 tucked away in a folder.
If nothing turns up on paper, you can file a Freedom of Information Act request with USCIS using Form G-639. The request lets you ask for records from your own immigration file, and you don’t need to know your A-Number to submit it, though more identifying information speeds the search.10U.S. Citizenship and Immigration Services. Freedom of Information/Privacy Act Request USCIS recommends its online FOIA portal at uscis.gov/foia over the paper form because online requests move more efficiently. FOIA responses can still take weeks or months depending on the backlog, so this isn’t a fix for a filing deadline that’s close.
If you have an active case with USCIS and an online account, your case status page or account profile may display the number. An immigration attorney who represented you in the past may also have it on file.