The Alien Registration Number or A-Number is a unique identification code granted to you by USCIS, and it is like your personal ID in the immigration system. Your file management and benefit application through the immigration process cannot go without this number.
In this article, we will explain the following things:
- What is an Alien Registration Number?
- Who needs this number, and where can we find it?
- What is the importance of the A-number?
- Who is eligible for the A-number?
- Difference between A-Number and USCIS.
Therefore, if these are a few things that you want to know, keep on reading this blog till the end…
What Is An Alien Registration Number?

An Alien Registration Number, or A-Number, is a seven-to-nine-digit number the US government gives to foreign nationals. Immigration agencies like USCIS, ICE, and CBP use it to locate and combine a person’s records from various locations.
Anyone who applies for a green card gets an Alien Registration Number, no matter if they’re applying through family, work, or as a refugee or asylum. So, all immigrants—people who plan to live in the United States permanently—receive one.
Usually, non-US citizens who are in the US temporarily, say for example, a business person or tourist with a visa, don’t get an Alien Registration Number since they’re seen as short-term visitors, not permanent residents.
Where Can I Find My Alien Registration Number?
Once you apply for a green card, the USCIS will send you papers with your Alien Registration Number on them. It’ll be on the notice you receive when they get your application, plus any approval notices and just about any other letter from them.
On most USCIS forms, your Alien Registration Number will show up as A# near the top of the first page, so it’s easy to spot.
If you apply outside the U.S., you can find your A-number on the Immigrant Data Summary and the USCIS Immigrant Fee handout, which they give you during your consular interview. And once your application gets approved, your A-number will be on the visa in your passport.
After you get your actual green card, your Alien Registration Number, or USCIS#, will be on both the front and back.
What Is The Importance Of A-Number?
The A-Number serves as a means to track your immigration records. You will require it for numerous different tasks:
- Working on immigration applications and forms (e.g., Form I-130, I-485)
- Verifying your USCIS case status
- Obtaining a copy of your immigration file (Form G-639 FOIA request)
- Interacting with USCIS or EOIR
Important: When filling out USCIS application forms, the form usually asks for a 9-digit number. If your number is less than nine digits, then to make it nine digits long, insert a zero after the “A” and before the first digit. For instance, “A12345678” becomes “A012345678.”
Eligibility For Alien Registration Number

Judging other people’s work in your field can help you meet an O1 visa requirement. This judging can be in a competition, like an awards panel or a grants committee.
It could also be when you assess someone’s work, like a research paper, presentation, or even a grant proposal.
Basically, some group thinks you’re the best person to assess others’ work. This shows USCIS that you’re among the top people in your field.
If you think you meet the judge of others’ requirements, and at least two more O1 visa criteria, then go ahead with your application!
Read Also: Domicile Vs Residence: Understanding The Critical Difference & Legalities Involved
Where Can I Use My Alien Registration Number?
Your Alien Registration number can be of several uses. Some of the times when you will need it are as follows:
For Is Filing An Immigration-Related Case
What is an Alien Registration Number (A-Number)? It is a vital piece of information that is intimately linked with all your dealings with the U.S. immigration system.
The most essential use of such a number is that it acts as a single key binding all your records and history of immigration together. As a result, on any form of application for immigration benefits, it will be your A-Number that will be the one to be filled in.
They Can Track Their Case Status
Besides that, a number assigned to you by USCIS will be the very thing allowing one to go online and find out the status of the immigration case.
It might be the case that you are awaiting a return of the application or merely wanting to progress the immigration journey.
In either case, the Alien Registration Number is what enables you to find out information regarding the same from the U.S. Citizenship and Immigration Services (USCIS) website and by calling USCIS directly.
For Accessing Other Services And Benefits In The US
Finally, the A-Number is a pivotal element when working with other government agencies or accessing a variety of services and benefits.
What an alien registration number does is that it officially identifies you as someone who is lawfully in the U.S.
It may be the case when you are permitted to have a driver’s license, a social security account, or other documents that are of equal importance to you in the process of conducting your business here that they ask the number.
Is A-Number The Same As USCIS Number?
You will be able to see your Alien Registration Number on your receipt notices. Besides that, there’s also a USCIS case number or receipt number. Use this one to track your application and see what’s up with it.
Basically, your A-number is yours forever, but the case number is just for that specific application. So, let’s say that you apply for a green card now and then for citizenship later. In that case, each application gets its own USCIS case number. But your A-number stays the same.
You can tell them apart by how they look. An A-number is always 7, 8, or 9 digits long. A USCIS case number? It’s 13 characters – starts with three letters (like MSC or EAC), then ten numbers.
One thing that can trip you up is when people say USCIS number or USCIS#, but they actually mean your Alien Registration Number. Just double-check that you’re using the right numbers!