Where Can I Find My A-Number on Immigration Documents?

Your A-Number, or Alien Registration Number, is printed on nearly every immigration document the Department of Homeland Security has ever issued to you, so the fastest place to find your A-Number on immigration documents is your Green Card, work permit, immigrant visa stamp, or any USCIS notice sitting in your files. It’s a seven-, eight-, or nine-digit number that stays with you for life and links every application and record DHS holds under your name.¹ If none of those documents are within reach, you can retrieve the number by filing a FOIA request online with USCIS.

On Your Green Card

Most people find it here first. Cards issued after May 10, 2010, display a nine-digit “USCIS Number” on the front, which is your A-Number without the “A” prefix.² The same number is also printed on the back. USCIS has released several card designs since 2010, and the fields sit in slightly different spots on each version, but every one of them shows both the USCIS Number and the A-Number.³

On older Green Cards issued before May 2010, the number is labeled “A#” and usually appears near the top of the card next to your name, date of birth, and fingerprint. These older cards keep the “A” prefix, so the format looks like “A012345678” rather than a bare string of digits.³

On Your Work Permit

Your Employment Authorization Document also carries the A-Number on the front of the card. Depending on the version, the label reads “A#,” “AR#,” or “USCIS#,” but the nine digits are the same as on your Green Card.² Employers use it during I-9 verification, so it’s printed in a prominent spot.

On Immigrant Visa Documents From Consular Processing

If you were issued an immigrant visa abroad, several documents from that process display your A-Number.

The immigrant visa stamp in your passport lists it as the “Registration Number.”⁴
The immigrant data summary, which was stapled to the packet handed to you at your embassy or consulate appointment, shows your A-Number and Department of State Case ID at the top.⁴
The USCIS Immigrant Fee handout, which the consular officer gave you with payment instructions, prints your A-Number and DOS Case ID in the top right corner.⁴

These papers are easy to lose after you arrive in the United States. Photograph or scan them while they’re still in hand.

On USCIS Notices

Any Form I-797 (Notice of Action) that USCIS has mailed you will typically show your A-Number near the top, in the applicant or beneficiary information section. If you’ve filed for a work permit, adjustment of status, or almost any other benefit, you’ve received at least one I-797 receipt or approval notice. Check the upper portion where your biographical details appear.

Don’t Confuse the A-Number With Other Numbers

Immigration paperwork uses several different tracking numbers, and mixing them up is one of the more common mistakes on applications. The A-Number is yours for life and ties together every interaction you’ve had with DHS. Two others look similar but do different work:

A receipt number, sometimes called a case number, is a 13-character code starting with three letters (like EAC, WAC, or IOE) followed by 10 digits. USCIS assigns a new one to each application or petition, so you’ll accumulate many receipt numbers over time but keep only one A-Number. Receipt numbers appear on your I-797 notices.
A Social Security Number is a nine-digit number issued by the Social Security Administration for tax, employment, and banking purposes. Your SSN and A-Number sit in completely separate systems. Permanent residents need both, and an SSN application actually uses your immigration documents, including your A-Number, as supporting evidence.⁵

When you fill out an immigration form, read the field label carefully. Entering a receipt number where the A-Number belongs, or the other way around, can trigger a processing delay or a Request for Evidence.

If You Can’t Find Any of These Documents

When every card and notice is missing, you can request your immigration records, called your A-File, from USCIS through a Freedom of Information Act or Privacy Act request. As of January 22, 2026, USCIS requires these requests to be submitted online. Paper submissions by mail are no longer the standard method.⁶

Create a USCIS account at first.uscis.gov, then submit your FOIA request through the portal. You’ll need your full legal name, date of birth, and place of birth so USCIS can locate the right file. Online submission puts the request in line for processing immediately, and USCIS will email you when your records are ready to download from your account.⁶ Form G-639 is still available for reference, but the online portal is now the expected channel.⁷

Processing times vary. If you have an upcoming hearing before an immigration judge, USCIS will prioritize your request, and you’ll need to include a copy of your Notice to Appear, Order to Show Cause, Notice of Referral to Immigration Judge, or a written notice of a future scheduled hearing.⁶ Without that kind of urgency, expect several weeks to several months depending on current backlogs. There’s no upfront fee to file, though USCIS may notify you after review if any charges apply.

1
U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number
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USCIS. USCIS Number
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U.S. Citizenship and Immigration Services. List A Documents That Establish Identity and Employment Authorization
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U.S. Citizenship and Immigration Services. Immigrant Fee Payment – Tips on Finding Your A-Number and DOS Case ID
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Social Security Administration. Social Security Numbers for U.S. Permanent Residents
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U.S. Citizenship and Immigration Services. Request Records through the Freedom of Information Act or Privacy Act
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U.S. Citizenship and Immigration Services. USCIS Form G-639 – Freedom of Information/Privacy Act Request