Alien Registration Number

An alien registration number, often referred to as an A-Number, is a unique identifier assigned to certain non-citizens by United States Citizenship and Immigration Services (USCIS). A-Numbers play a significant role in your long-term interactions with the immigration system—even naturalized citizens retain their A-Numbers. Understanding your A-Number and knowing what documents it is on will help you throughout your immigration process and stay in the U.S. An experienced immigration lawyer in Chicago can provide invaluable guidance on your alien registration number and the green card application process.

What Is Your A-Number?

An alien registration number (A-Number) is a personal identification number issued by USCIS to non-citizens to track immigration records. It is a unique seven- to nine-digit number that serves as a permanent identifier. You will use your A-Number when filling out all immigration forms throughout your lifetime. 

In 2026, U.S. Citizenship and Immigration Services (USCIS) has heightened its review and screening procedures for individuals with A-Numbers, including asylees, refugees, and applicants with pending adjustment-of-status cases. The agency has also placed greater emphasis on fraud detection and record verification. As a result, understanding the significance of your alien registration number and ensuring it is used accurately and consistently has never been more vital.

Alien Number Types

Most A-Numbers are nine digits, but some may be seven or eight digits. If your A-Number is less than nine digits, place the correct number of zeros at the front of the number to make it nine.

Example: 1234567 would become 001234567.

Where Do I Find My Alien Registration Number?

A-Numbers are typically on all of your immigration documents, including your:

• Initial notice that USCIS received your application 
• Approval notices
• Immigrant visa card (You can find your A-Number under “Registration Number” on the top right of the visa stamp)
• Permanent resident green card (You can find your A-Number on the front and back of your green card under “USCIS#”)
• Employment Authorization Document (EAD)
• Almost all immigration documents

The Difference Between an Alien Registration Number and a USCIS Number

Your alien registration number is also known as your USCIS number—but this USCIS number differs from your USCIS case number, which serves a different purpose.

Your USCIS number is your A-Number, which can be located on your green card. Your USCIS case number is assigned to your specific application. These numbers will not match. Your A-Number will stay constant between applications; each application you submit will have a different USCIS case number.

You can tell the difference between your A-Number and your USCIS case number by the number of digits. Your A-Number will have seven, eight, or nine digits. Your USCIS case number will have 13 characters, consisting of three letters followed by 10 digits.

What Does the Government Use My Alien Registration Number For?

Your A-Number functions similarly to a Social Security Number. It’s the number assigned specifically to you as a form of identification. Your alien registration number is also used by the government in many other ways, including but not limited to:

• Identifying the number of resident immigrants in the United States
• Accessing your immigration records and other legal history
• Tracking your immigration history
• Connecting immigration agencies with your information, even in the case of a name change
• Security and background checks

At its most basic function, your A-Number is used as your main form of identification.

Am I Eligible for an A-Number?

Everyone who applies for a green card is eligible for an alien registration number. A-Numbers are necessary for all people who intend to or live permanently in the United States. Your eligibility is not determined by the type of green card you have (family, refugee, employment, etc.). If you are coming to the United States permanently, you will receive an A-Number.

Visa categories that are assigned an A-Number:

• Diversity Visa Lottery winners (when processed for permanent residence)
• Refugees and Asylees (and derivative family members)
• Special Immigrant Visa (SIV) holders
• Certain employment or family-based visa holders, after they apply for adjustment of status (green card)
• Fiancé(e) visa holders (K-1/K-2) — once they apply for a green card
• Visa holders placed in removal (deportation) proceedings, even if they originally had a temporary visa.
• DACA recipients
• An F-1 student who applies for Optional Practical Training (OPT) or STEM OPT

Who Is Not Eligible for an Alien Number?

Temporary non-immigrant visa recipients are not given A-Numbers. Short-term stays in the United States do not need documents with an A-Number.

Frequently Asked Questions About Alien Registration Numbers

Contact an Immigration Attorney

If you have any questions about your alien registration number or the immigration process in general, please reach out to the experienced Chicago immigration attorneys at Scott D. Pollock & Associates P.C. With over 30 years of expertise, we have in-depth knowledge and experience with all topics of immigration law. We can help you understand when and where your alien registration number may be required.

Call us anytime at 312-444-1940 or complete an online contact form today. We look forward to hearing from you!