The Alien Number on a green card is the nine-digit figure printed on the front of the card. On cards issued after May 10, 2010, it sits next to the label “USCIS#,” which is why many people don’t realize their card carries an Alien Number at all. On older cards, the same number appears next to an “A#” label. Either way, it’s the same identifier, and it follows you for life.1USCIS. A-Number/Alien Registration Number/Alien Number
Where to Look on the Card
If your Permanent Resident Card (Form I-551) was issued after May 10, 2010, turn it face up. The Alien Number is the nine-digit number printed next to “USCIS#.” The same number is also encoded on the back of the card.2U.S. Citizenship and Immigration Services. 13.1 List A Documents That Establish Identity and Employment Authorization
Older cards label the field “A#” instead. Placement varies by design because USCIS has redesigned the card every three to five years to reduce counterfeiting. Some legacy versions print it on the front; certain older designs place it on the back. If you have a pre-2010 card and can’t spot the number on one side, flip it over.
Why “USCIS#” and “A-Number” Are the Same Thing
This is where most of the confusion comes from. The “USCIS Number” printed on newer green cards is simply the Alien Registration Number without the “A” prefix. USCIS confirms the equivalence directly, and the Form I-9 employer handbook states it explicitly.3U.S. Citizenship and Immigration Services. 3.0 Completing Section 1: Employee Information and Attestation The USCIS glossary entry for “USCIS Number” points readers to “See also Alien Registration Number or Alien Number.”4USCIS. USCIS Number So when one form asks for a USCIS Number and another asks for an A-Number, you’re writing the same digits on both.
What the Number Is and How to Format It
The Alien Number is a seven- to nine-digit number assigned by the Department of Homeland Security when your immigration file is first created. In official records it’s preceded by the letter “A,” so a full version looks like A012345678. The number stays with you regardless of how your immigration status changes over time, from a student visa to a work visa to permanent residence and beyond.
If the number on your card has fewer than nine digits, pad it with zeros immediately after the “A” until it reaches nine digits when you enter it on a form. A12345678 becomes A012345678.5U.S. Citizenship and Immigration Services. Immigrant Fee Payment: Tips on Finding Your A-Number and DOS Case ID Getting the padding wrong is one of the most common reasons USCIS rejects forms, so it’s worth checking every time.
Other Documents That Show the Same Number
If the card is lost, expired, or just not within reach, your Alien Number appears on several other documents you may already have.
- The Immigrant Data Summary, often stapled inside the visa packet handed to new permanent residents on first entry, lists both the A-Number and a Department of State case ID.5U.S. Citizenship and Immigration Services. Immigrant Fee Payment: Tips on Finding Your A-Number and DOS Case ID
- The USCIS Immigrant Fee Handout, provided by the Department of State alongside your visa, carries it as well.
- An Employment Authorization Document (Form I-766) shows the A-Number on the front of the card.
- The immigrant visa foil stamped in your passport typically prints it near the top.
- USCIS Notices of Action (Form I-797), issued as receipts and approvals, show it near the top of the document.
One document that does not carry your Alien Number is the Form I-20 used by international students. The I-20 shows a SEVIS ID that begins with “N,” a separate identifier tied to the student record rather than the permanent immigration file.
When You’ll Be Asked for It
The Alien Number comes up on almost every immigration-related form you’ll ever complete, and on some that aren’t strictly immigration forms.
On Form I-9 for a new job, permanent residents enter their A-Number or USCIS Number in Section 1. Employees with other work authorization can provide the A-Number, Form I-94 admission number, or foreign passport number. The employer handbook confirms that USCIS Number and A-Number are interchangeable in that field.3U.S. Citizenship and Immigration Services. 3.0 Completing Section 1: Employee Information and Attestation
The naturalization application (Form N-400) requires your A-Number in the top-right corner of every page, along with your permanent resident date.6U.S. Citizenship and Immigration Services. Instructions for Application for Naturalization If yours has fewer than nine digits, add leading zeros just as you would elsewhere.
Form I-130, filed to sponsor a family member, asks for your A-Number in Part 2.7U.S. Citizenship and Immigration Services. Instructions for Form I-130, Petition for Alien Relative, and Form I-130A, Supplemental Information for Spouse Beneficiary Non-citizen U.S. nationals born in American Samoa or Swains Island are the exception and do not list one.
State agencies and federal benefits offices also use the number to run applicants through the Systematic Alien Verification for Entitlements (SAVE) system when you apply for certain benefits or a driver’s license.8U.S. Citizenship and Immigration Services. SAVE CaseCheck And when you apply for a Social Security card on Form SS-5, the DHS document you present (green card, EAD, or I-94) links to your record through the same A-Number.9Social Security Administration. Application for a Social Security Card (Form SS-5)
If You’ve Lost Track of Your A-Number
Check any immigration paperwork you still have before doing anything else. Old approval notices, expired EAD cards, the visa foil in a retired passport, and copies of past applications all carry the number. Form I-797 receipts, often filed away and forgotten, almost always show it near the top. Electronic correspondence from USCIS references it as well.
When no documents are available, you can request your records through the Freedom of Information Act or Privacy Act. As of January 22, 2026, all such requests for USCIS records must be submitted online through the USCIS FOIA portal; paper and email submissions are no longer accepted.10U.S. Citizenship and Immigration Services. Request Records through the Freedom of Information Act or Privacy Act You’ll need a USCIS account, and processing can take a while, so this route is best when you’re not up against a filing deadline.
If your Alien Number was originally listed on an Immigrant Data Summary or Immigrant Fee Handout that you’ve since lost, USCIS advises contacting the U.S. embassy or consulate that issued your visa to request a copy.5U.S. Citizenship and Immigration Services. Immigrant Fee Payment: Tips on Finding Your A-Number and DOS Case ID
Having the Number Is Not the Same as Having Status
One point worth being clear about: the Alien Number on your card does not, by itself, prove legal status, work authorization, or eligibility for benefits. USCIS states that alien registration is not an immigration status, and registration documentation does not establish employment authorization or confer any right or benefit under immigration law.11U.S. Citizenship and Immigration Services. Alien Registration Requirement The number is a lookup key. Your status comes from what’s actually recorded in the file it points to, and for green card holders that status is documented by the card itself.