Your Alien Registration Number, or A-Number, is the unique seven-, eight-, or nine-digit identifier the U.S. Department of Homeland Security assigns to you the first time you apply for or receive an immigration benefit. You’ll find it on the front of your green card, on your Employment Authorization Document, on the immigrant visa stamp in your passport, on USCIS approval and receipt notices, and on your Certificate of Naturalization. The number stays with you for life, even after you become a U.S. citizen.
What the A-Number Is
The A-Number is your personal identifier in the U.S. immigration system. DHS assigns it once, and it never changes. If you file ten applications over twenty years, or your status shifts from asylum seeker to lawful permanent resident to naturalized citizen, the same A-Number ties all of those records together.
On newer documents, you may see it labeled “USCIS#” instead of “A-Number.” The USCIS Number is the same nine-digit number, just renamed on Permanent Resident Cards issued after May 10, 2010.1U.S. Citizenship and Immigration Services. USCIS Number If your A-Number has fewer than nine digits, USCIS pads it with leading zeros; the underlying number is identical.
Where to Find Your A-Number
The number appears on most official immigration documents you’ve received from USCIS, the State Department, or an immigration court. The exact location varies by document, but it’s usually near the top of the page or on the front of the card.
Green Card (Form I-551)
On a Permanent Resident Card, the A-Number is printed on the front. Cards issued after May 2010 label it “USCIS#” rather than “Alien Registration Number,” but the number itself is the same.1U.S. Citizenship and Immigration Services. USCIS Number
Employment Authorization Document
On an EAD card, the A-Number also appears on the front, labeled “USCIS#.” The format matches what you see on a green card.
Immigrant Visa Stamp
If you entered the United States on an immigrant visa, the number is printed in the top right area of the visa stamp inside your passport, labeled “Registration Number.”
USCIS Approval and Receipt Notices (Form I-797)
Form I-797 notices display the A-Number near the top of the first page. If you adjusted status from inside the United States, you likely received your A-Number for the first time on the receipt notice generated when USCIS accepted your application.
Immigrant Data Summary
If you attended a visa interview at a U.S. embassy or consulate, an immigrant data summary was stapled to the front of your sealed visa package. Your A-Number and DOS Case ID appear at the top of that sheet.2U.S. Citizenship and Immigration Services. Immigrant Fee Payment: Tips on Finding Your A-Number and DOS Case ID
Certificate of Naturalization (Form N-550)
Even after you become a U.S. citizen, your A-Number doesn’t disappear. It’s printed on your Certificate of Naturalization under the label “USCIS Registration No.” in the personal description section.3U.S. Citizenship and Immigration Services. Form N-550, Certificate of Naturalization
Who Has an A-Number and Who Doesn’t
Not every non-citizen in the United States has one. DHS assigns an A-Number when you apply for or are granted certain immigration benefits, when you’re placed in removal proceedings, or when you’re otherwise registered in the system. Common categories include lawful permanent residents, asylum applicants, refugees, and people with approved employment-based or family-based petitions.4U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number
Tourists and short-term visitors typically never see an A-Number. F-1 students are tracked primarily through their SEVIS number, and spouses of H-1B or L-1 workers may not receive one until they file for adjustment of status or another benefit that triggers assignment. If a form asks for your A-Number and you’ve never been assigned one, write “N/A.”5U.S. Citizenship and Immigration Services. Instructions for Form I-765, Application for Employment Authorization
When You’ll Need It
Beyond immigration filings, your A-Number comes up in several practical situations.
On Form I-9, Section 1 asks for your USCIS Number or A-Number if you attest to being a lawful permanent resident. Non-citizens authorized to work under other categories can provide either a USCIS Number, an I-94 admission number, or a foreign passport number.6U.S. Citizenship and Immigration Services. Instructions for Form I-9, Employment Eligibility Verification
If you received an immigrant visa abroad, you’ll need your A-Number and DOS Case ID to pay the USCIS Immigrant Fee online before your green card can be produced.2U.S. Citizenship and Immigration Services. Immigrant Fee Payment: Tips on Finding Your A-Number and DOS Case ID
Nearly every USCIS form asks for your A-Number if one has been assigned. Using the wrong number, or leaving the field blank when you do have one, can slow processing or cause records to be linked incorrectly.
How to Recover a Lost A-Number
Losing track of the number is more common than you might think, especially after years without a filing.
Check Every Document You Already Have
Before filing anything, look through every immigration document in your possession: green cards (current or expired), EAD cards, I-797 notices, visa stamps, and naturalization certificates. Expired documents still carry the correct A-Number.
File a FOIA or Privacy Act Request
If you can’t find any documents, request copies of your immigration records through a Freedom of Information Act or Privacy Act request. As of January 22, 2026, DHS no longer accepts paper or emailed FOIA requests. All requests must be submitted online through the USCIS FOIA portal at first.uscis.gov, and you’ll need to create a USCIS account first.7U.S. Citizenship and Immigration Services. Request Records through the Freedom of Information Act or Privacy Act Requesting a single specific document is faster than asking for your entire immigration file.
Call the USCIS Contact Center
You can reach the USCIS Contact Center at 1-800-375-5283 (TTY: 1-800-767-1833) for help with pending applications and immigration inquiries. Have your full name, date of birth, and any receipt numbers ready so the representative can locate your records.7U.S. Citizenship and Immigration Services. Request Records through the Freedom of Information Act or Privacy Act
Ask an Immigration Attorney
An immigration attorney or accredited representative can file a FOIA request on your behalf with proper authorization.7U.S. Citizenship and Immigration Services. Request Records through the Freedom of Information Act or Privacy Act Fees vary widely, so ask for a flat-fee quote before hiring someone for what is essentially a straightforward records request.
A-Number vs. Other Numbers in Your Paperwork
Several different numbers appear on immigration and government paperwork, and mixing them up causes real problems on applications.
Social Security Number
A Social Security Number is a nine-digit number issued by the Social Security Administration for tax and employment purposes. Some non-citizens receive an SSN that is restricted to work only with DHS authorization, and others receive one marked “not valid for employment.”8Social Security Administration. Types of Social Security Cards Your SSN doesn’t replace your A-Number on immigration forms, and your A-Number doesn’t replace your SSN on tax returns.
USCIS Receipt Number
A receipt number is a 13-character code (three letters followed by ten digits) that USCIS assigns to each individual application or petition.9U.S. Citizenship and Immigration Services. Receipt Number You get a new receipt number every time you file something. Receipt numbers track a specific case; your A-Number tracks you.
SEVIS ID
F-1 and J-1 students and exchange visitors are assigned a SEVIS ID that begins with the letter “N.” On a Form I-20, it appears in the top right corner of the first page. SEVIS IDs are managed by the Student and Exchange Visitor Program and are separate from the A-Number system. Most students don’t receive an A-Number unless they later apply for a benefit like adjustment of status or post-graduation work authorization.
Individual Taxpayer Identification Number
The IRS issues ITINs to people who need to file a tax return but aren’t eligible for a Social Security Number. ITINs are nine digits starting with the number 9. An ITIN is purely a tax identifier. It doesn’t grant work authorization or immigration status, and it has no connection to your A-Number.
Protecting Your A-Number
USCIS classifies your A-Number as personally identifiable information alongside your Social Security Number, passport number, and biometric data.10U.S. Citizenship and Immigration Services. USCIS Policy Manual, Volume 1, Part A, Chapter 7 – Privacy and Confidentiality Treat it with the same care you’d give your SSN. Don’t post it on social media, don’t send it in unsecured emails, and don’t give it to anyone without a legitimate need for it. Someone who obtains your A-Number along with other personal details can potentially interfere with your immigration record or file fraudulent applications. Keep copies of your immigration documents in a secure place, and verify who you’re dealing with before sharing the number with an employer or attorney.