How to Find Your Alien Registration Number (A-Number)

You have finally sat down to fill out your marriage green card forms. You have your passport, your marriage certificate, and your coffee ready. You feel prepared.

Then, you look at Form I-130 or Form I-485, and right near the top, it asks for an Alien Registration Number (A-Number).

Panic sets in. Do you have one? Did you lose it? Is it the same as your visa number?

Take a deep breath. This is one of the most common stumbling blocks for couples starting the immigration journey. The good news is that finding this number is usually straightforward once you know where to look.

In this guide, we will explain exactly how to find alien registration number locations on various documents, who actually has one, and what to do if yours is missing.

What is an Alien Registration Number?

Before you tear your house apart looking for it, it helps to know what you are looking for.

An Alien Registration Number—often called an A-Number, Alien Number, or USCIS Number—is a unique identification number assigned to a non-citizen by the Department of Homeland Security (DHS).

Think of it like a Social Security Number, but strictly for immigration purposes. Once you are assigned an A-Number, it sticks with you for life. Even if you become a naturalized U.S. citizen later, that A-Number will still be in your historical file.

What Does it Look Like?

An A-Number consists of the letter “A” followed by seven, eight, or nine digits.

• Example: A-123-456-789

Note: On USCIS forms, if your A-Number has fewer than 9 digits, you should add zeros after the “A” to make it fit. For example, if your number is A-12345678, you would write A-012345678.

Who Has an A-Number (And Who Doesn’t)?

Not every foreign national in the United States has an A-Number. If you are here on a short trip, you probably don’t have one yet.

You LIKELY HAVE an A-Number if:

• You are a Lawful Permanent Resident (you have a Green Card).
• You have applied for a Green Card (permanent residence).
• You have a Work Permit (Employment Authorization Document/EAD).
• You are on an F-1 student visa and received authorization to work (OPT).
• You have been in deportation or removal proceedings.

You LIKELY DO NOT HAVE an A-Number if:

• You are in the U.S. on a tourist visa (B-1/B-2).
• You are on a temporary business visa.
• You are an F-1 student who has not yet applied for work authorization (OPT).
• You have never applied for any immigration benefit with USCIS.

If you are a U.S. citizen spouse petitioning for your partner, you (the citizen) do not have an A-Number. Only the immigrant spouse (the beneficiary) will have or will receive one.

How to Find Alien Registration Number: Check Your Documents

If you fit the criteria for having an A-Number, it will be printed on documents you have already received from USCIS or ICE. Here is a step-by-step breakdown of where to look.

1. On Your Permanent Resident Card (Green Card)

If you already have a Green Card (perhaps you are renewing it or applying for citizenship), finding your A-Number is easy.

Current Green Cards (Issued after 2010):

• Look at the front of the card.
• Find the label “USCIS#”.
• The 9-digit number listed there is your A-Number. It usually does not have the letter “A” in front of it on the card, but it is the correct number.

Older Green Cards:

• 1997–2004 versions: Look for “A#” listed on the front.
• Legacy versions: Look on the front for numbers starting with A.

How to Read Your Green Card: Every Field Explained

2. On Your Employment Authorization Document (EAD)

If you have a work permit (EAD card), commonly issued to F-1 students on OPT or spouses waiting for their green card:

• Look at the front of the card.
• Under the heading “USCIS#”, you will see a 9-digit number.
• This is your A-Number.

3. On Your Immigrant Visa

If you applied for your Green Card from outside the United States (Consular Processing), you received an immigrant visa stamp in your passport to enter the U.S.

• Open your passport to the visa page.
• Look at the top right area of the visa stamp.
• Find the field labeled “Registration Number” or “A-Number.”
• Warning: Do not confuse this with the “Visa Number” (usually in red) or the “Control Number.”

4. On the Notice of Action (Form I-797C)

When you send an application to USCIS, they send you a receipt letter called a Notice of Action (I-797C). This confirms they received your case.

• Look at the top right corner of the document.
• Find the box labeled “USCIS#” or “A-Number.”
• If you are just starting your application, this box might be blank on the very first receipt. However, if you have applied for anything in the past (like student work authorization), check those old notices.

5. On the Immigrant Data Summary

If you applied for your Green Card at a U.S. consulate abroad, the officer may have stapled a summary sheet to the front of your immigration packet.

• Look for the field labeled “A-Number” at the top of the summary page.

Common Confusion: A-Number vs. Other Numbers

Immigration forms are full of different ID numbers. It is very easy to grab the wrong one. Let’s clear up the confusion so you don’t write the wrong number on your form.

A-Number vs. USCIS Online Account Number

This is the most common mistake we see in 2026.

• A-Number: 9 digits. This is your permanent file ID.
• USCIS Online Account Number: 12 digits. This is a login ID for the online portal.

You might have an A-Number but not have an Online Account Number. If the form asks for the Online Account Number and you don’t have one, just leave it blank or write “None.”

A-Number vs. Visa Number

• A-Number: Your file number (starts with A).
• Visa Number: Usually printed in red on the bottom right of your visa stamp in your passport. This is specific to that entry document, not your permanent file.

A-Number vs. Social Security Number (SSN)

• A-Number: Issued by DHS/USCIS for immigration.
• SSN: Issued by the Social Security Administration for taxes and work.
• They are completely different. Never put your SSN where the form asks for an Alien Registration Number.

The Ultimate Marriage Green Card Documents Checklist (2026 Update)

Real-World Scenarios: When Do You Get an A-Number?

Sometimes, understanding the timeline helps you figure out if you even have a number to find.

Scenario 1: The F-1 Student (Mateo)

Mateo came to the U.S. on an F-1 student visa to study engineering.

• Year 1-3: Mateo does not have an A-Number. His visa has a control number, but no A-Number.
• Year 4: Mateo applies for Optional Practical Training (OPT) to work after graduation. He files Form I-765.
• The Result: When his OPT is approved, he gets an EAD card. He is now assigned an A-Number. It is printed on his EAD card. He will use this number for all future immigration forms.

Scenario 2: The Tourist Spouse (Elena)

Elena entered the U.S. on a B-2 tourist visa to visit friends. She met her future wife, Sarah (a U.S. citizen), and they decided to get married.

• Arrival: Elena does not have an A-Number.
• Marriage: She still does not have an A-Number.
• Filing: Sarah and Elena prepare the Greenbroad package (Forms I-130 and I-485). On the forms, Elena leaves the “A-Number” question blank because she doesn’t have one yet.
• The Result: About 2-3 weeks after mailing the package, they receive a receipt notice (I-797). Elena has now been assigned an A-Number, which appears on that receipt. She will use it for her interview and biometric appointment.

What If I Can’t Find My A-Number?

If you know you have an A-Number (because you had a work permit or green card in the past) but you lost the documents, you have a few options:

1. Freedom of Information Act (FOIA) Request

You can request a copy of your immigration file (A-File) from USCIS. This is free, but in 2026, processing times can take several weeks to months.

• File Form G-639.
• This is the most reliable way to get your number if you have lost absolutely everything.

2. Check with Family or Employers

Did your previous employer file for your visa? HR might have a copy of your old I-129 or I-797 notices. Did a parent file for you when you were a child? Check their old paperwork.

3. Schedule an Appointment

While difficult to get, you can try to schedule an in-person appointment at a local USCIS field office through the USCIS Contact Center to request your number. This should be a last resort.

Resource: Official USCIS Page on A-Numbers

Frequently Asked Questions

Here are the most common questions our Greenbroad customers ask about how to find alien registration numbers.

1. Do I need an A-Number to file for a marriage green card?

If you have never been assigned one (for example, you are a tourist filing for the first time), no. You can leave that field blank. USCIS will assign you one after they receive your application. If you do have one from a previous application (like student OPT), you must include it.

2. Is the “Admission Number” on my I-94 the same as the A-Number?

No. Your I-94 Admission Number tracks your specific arrival into the U.S. It changes every time you enter the country. Your A-Number tracks your identity and never changes.

3. I became a U.S. Citizen. Do I still use my A-Number?

Generally, no. Once you are a U.S. citizen, you will list your citizenship on forms. However, your A-File still exists in the government archives under that number.

4. What if I write the wrong A-Number on my application?

If you make a mistake, it can cause delays because USCIS may struggle to link your new application with your historical file. If you realize the error after filing, you may need to send a letter correcting the record or update the officer during your interview.

5. Does my U.S. Citizen spouse need an A-Number?

If your spouse was born in the U.S., they do not have an A-Number. If they were a permanent resident before becoming a citizen, they do have one, but they typically do not need to list it on the I-130 petition where it asks for their information (unless specifically requested).

Conclusion: Don’t Let One Number Stop You

Immigration forms are designed to be precise, but that often makes them confusing. Finding your Alien Registration Number is just one small step in building your future in the United States.

Remember: If you have one, it is likely in your wallet (on a card) or in your file cabinet (on a notice). If you don’t have one yet, don’t worry—USCIS will give you one soon.

Disclaimer: Greenbroad is not a law firm and cannot provide legal advice or legal representation. The information contained in this article is for informational purposes only and is not a substitute for advice from a qualified attorney. If your case involves criminal history, previous deportations, or complex legal issues, please consult an immigration lawyer.