What Is a Permanent Resident Number and Where to Find It

A permanent resident number is the unique identifier the Department of Homeland Security assigns to every person granted lawful permanent resident status in the United States. It is the same thing as your A-Number, Alien Registration Number, or USCIS Number — different labels, one number.¹ It stays with you for life, even after you naturalize as a U.S. citizen.

What the Number Looks Like

The number is seven, eight, or nine digits long, depending on when your immigration record was created. On Green Cards issued after May 10, 2010, it appears as a nine-digit “USCIS Number” on the front of the card.² Older cards and documents may show a shorter version.

When a government form asks for your A-Number and yours has fewer than nine digits, pad the front with zeros until you reach nine. A1234567 becomes A001234567.³

Where to Find Your Permanent Resident Number

On Your Green Card

The easiest place to find it is on your Green Card (Form I-551). On current cards, the number is printed on both the front and the back, labeled as either the “USCIS Number” or the “A-Number.”⁴

Watch out for the separate 13-character number printed on the back of the card. That code identifies the physical card, not you. It starts with three letters followed by ten digits, and a new one is issued every time you get a replacement card.

On Other Immigration Documents

If your Green Card isn’t in front of you, several other documents carry the same number:

The visa foil inside your passport, where it’s labeled “Registration Number.”⁵
Your immigrant data summary.
USCIS approval and receipt notices.
A Notice to Appear, if you’ve had immigration court proceedings.

If You Can’t Find It Anywhere

When none of your documents are available, file a Freedom of Information Act request with USCIS to retrieve your records. USCIS recommends filing online at uscis.gov/foia, but you can also mail a paper Form G-639. If you don’t remember your A-Number, leave that field blank and fill in as much identifying information as you can — your full name, date of birth, country of birth, and any receipt numbers — so USCIS can locate your file.⁶ You can also call the USCIS Contact Center at 800-375-5283 for help.

Don’t Confuse It With These Other Numbers

Immigration paperwork uses several numbers that look alike, and mixing them up is one of the most common form errors.

The A-Number, or permanent resident number, is your personal, lifelong identifier: seven to nine digits, assigned to you as an individual.¹
A receipt number, or case number, is a 13-character code (three letters plus ten digits) assigned to a specific application or petition. Each filing gets its own receipt number, so you may accumulate several over the years.⁷
The Green Card number, printed on the back of your card, is a separate 13-character identifier tied to that physical card. It looks similar to a receipt number in format, and it changes whenever you replace the card.
Your Social Security Number is a nine-digit number issued by the Social Security Administration. The SSN is used by the IRS, employers, and banks; the A-Number is used within the immigration system. They serve completely different systems.

Rule of thumb: when a form asks for your “USCIS Number,” it wants your A-Number. When it asks for a “receipt number,” it wants the 13-character code from a specific filing.

How the Number Gets Used

Employment Verification

Every employer in the United States has to verify that new hires are authorized to work by completing Form I-9. When you fill out Section 1 as a lawful permanent resident, you enter your A-Number directly on the form.⁸ You then show your Green Card or another List A document, which your employer records in Section 2.⁹

Returning From International Travel

When you re-enter the United States after a trip abroad, Customs and Border Protection officers use your Green Card and A-Number to confirm your permanent resident status before admitting you.¹⁰

Public Benefits and REAL ID

Agencies that administer certain public benefits verify immigration status through the SAVE (Systematic Alien Verification for Entitlements) system. To open a SAVE case, the agency submits your A-Number along with your name and date of birth, and SAVE returns a verification response, typically within seconds.¹¹ State DMVs use SAVE the same way when you apply for a REAL ID-compliant driver’s license using your Green Card.¹²

Applying for Citizenship

The A-Number follows you into naturalization. On Form N-400, Application for Naturalization, you write your A-Number in the top right corner of every page, and USCIS uses it to pull your full immigration history.³ After you naturalize, the same number appears on your Certificate of Naturalization. You surrender your Green Card at that point, but the number itself stays in your permanent record.¹³

Keeping Your Number Safe

Your A-Number is sensitive personal information. Someone who has your A-Number, name, and date of birth could potentially misuse your immigration status or commit identity fraud. Treat it the way you’d treat your Social Security Number: don’t share it casually, and be careful about sending it through unsecured channels.

If you suspect your A-Number or immigration identity has been compromised, report the theft to the Federal Trade Commission at IdentityTheft.gov or by calling 1-877-438-4338. Place fraud alerts and credit freezes with the three major credit bureaus, and contact the fraud department at your bank.¹⁴ Report the issue to USCIS through the Contact Center at 800-375-5283 as well, so they can note the compromise in your file.

1
U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number (A-Number or A#)
2
U.S. Citizenship and Immigration Services. USCIS Number
3
U.S. Citizenship and Immigration Services. Form N-400, Instructions for Application for Naturalization
4
U.S. Citizenship and Immigration Services. List A Documents That Establish Identity and Employment Authorization
5
U.S. Citizenship and Immigration Services. Immigrant Fee Payment: Tips on Finding Your A-Number and DOS Case ID
6
U.S. Citizenship and Immigration Services. Form G-639, Freedom of Information/Privacy Act Request
7
U.S. Citizenship and Immigration Services. Receipt Number
8
U.S. Citizenship and Immigration Services. Instructions for Form I-9, Employment Eligibility Verification
9
U.S. Citizenship and Immigration Services. I-9, Employment Eligibility Verification
10
U.S. Citizenship and Immigration Services. Travel Documents
11
U.S. Citizenship and Immigration Services. SAVE Verification Process
12
Transportation Security Administration. REAL ID Frequently Asked Questions
13
U.S. Citizenship and Immigration Services. Chapter 3 – Certificate of Naturalization
14
USAGov. Identity Theft