What Is a USCIS Number and Where to Find It?

A USCIS number is the nine-digit identifier that the Department of Homeland Security assigns to a foreign national who applies for or receives an immigration benefit.¹ It’s the same number as your Alien Registration Number (A-Number or A#), and you’ll find it printed on your Green Card, your Employment Authorization Document, your immigrant visa stamp, and other official immigration documents. Once assigned, it stays with you permanently, even after you naturalize.

USCIS Number and A-Number Are the Same

The USCIS glossary defines the A-Number as a unique seven-, eight-, or nine-digit number assigned by DHS to a foreign national, and cross-references it directly to the USCIS number.² Older documents label it “Alien Number” or “A#”; newer ones say “USCIS#.” When a form asks for your USCIS number, enter your A-Number.

One detail catches people out. A-Numbers issued years ago were sometimes only seven or eight digits. If yours is shorter than nine digits, add a zero right after the “A” to bring the total to nine. So A12345678 becomes A012345678.³ Skipping that pad is one of the most common reasons online forms and fee payments get rejected.

Where to Find Your USCIS Number

The number is printed on several documents. Where to look depends on which one you have in front of you.

Permanent Resident Card (Green Card). On cards issued after May 10, 2010, the number appears on the front under the label “USCIS#.” On older cards, look for “A#.” It also appears on the back.¹
Employment Authorization Document (EAD). On the front of the card, labeled “USCIS#,” “A#,” or “AR#.”⁴
Immigrant visa stamp. If you went through consular processing, the A-Number is printed on the stamp as the “Registration Number.”³
USCIS Immigrant Fee handout. The handout the consular officer gave you at your visa interview shows the A-Number and DOS Case ID in the top right corner.³
USCIS approval and receipt notices (Form I-797). The A-Number typically appears near the top of the notice.
Certificate of Naturalization. Your USCIS registration number is printed on the certificate.⁵

If you use a myUSCIS online account, case documents stored there may display your A-Number too.

Not the Same as a Receipt Number

A USCIS receipt number is a different thing. It’s a 13-character tracking code — three letters followed by ten digits — that USCIS generates for a single application or petition.⁶ You use it to check the status of that one filing. Over the years you may collect several receipt numbers, but your USCIS number stays the same across all of them.

Not the Same as an Online Account Number

When you create a myUSCIS account, the system assigns you an online account number. That’s a login identifier for the web portal, not your A-Number. Some newer forms ask for it in a separate field, and leaving it blank is fine if you don’t have an online account. Don’t enter your online account number where a form asks for your USCIS number or A-Number. They aren’t interchangeable.

Using Your USCIS Number for a Job

The number comes up early in any new job. When you complete Form I-9, you must enter your USCIS number or A-Number if you are a lawful permanent resident. Workers with temporary work authorization can provide a USCIS number, a Form I-94 admission number, or a foreign passport number.⁷ If your employer uses E-Verify, the system checks the I-9 information electronically against DHS and Social Security Administration records.⁸ A mistyped or unpadded A-Number can trigger a mismatch, so verify the digits before your employer submits.

Your Number After You Naturalize

Becoming a U.S. citizen doesn’t erase your A-Number. It’s printed on your Certificate of Naturalization as the “USCIS registration number.”⁵ You may still need it when sponsoring a family member, applying for your first passport, or dealing with any process that references your prior immigration history. Keep a record after you surrender your Green Card at the ceremony.

If You Can’t Find Your Number

The fastest option is to call the USCIS Contact Center at 800-375-5283. A representative can look up your record using other identifying information.⁹ If you got your immigrant visa through a U.S. embassy or consulate, that office can also send you a copy of your immigrant data summary, which shows the A-Number.³

For a formal route, you can file Form G-639, a Freedom of Information Act and Privacy Act request for your own immigration records. The form is built for people who don’t know their A-Number; the instructions say to leave that field blank if you can’t remember it or don’t have one.¹⁰ FOIA requests take time, so treat this as a backup rather than a first step.

If You’ve Never Been Assigned One

Not everyone has a USCIS number. If you’re filing your first immigration application and have never been assigned an A-Number, you don’t have one to enter. Most forms account for this by labeling the field “A-Number (if any)” or telling you to leave it blank. USCIS will assign a number when it processes your application. Don’t invent a number or fill in zeros as a placeholder. Blank is the correct answer when you genuinely haven’t been assigned one yet.

1
U.S. Citizenship and Immigration Services. USCIS Number
2
U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number (A-Number or A#)
3
U.S. Citizenship and Immigration Services. Immigrant Fee Payment: Tips on Finding Your A-Number and DOS Case ID
4
FBI. Locating the Alien Number
5
U.S. Citizenship and Immigration Services. Chapter 3 – Certificate of Naturalization
6
U.S. Citizenship and Immigration Services. Receipt Number
7
U.S. Citizenship and Immigration Services. Instructions for Form I-9, Employment Eligibility Verification
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E-Verify. E-Verify User Manual
9
U.S. Citizenship and Immigration Services. Contact Us
10
U.S. Citizenship and Immigration Services. Form G-639, Freedom of Information/Privacy Act Request