What Is An Alien Registration Number And Why Is It Important?

Every step of the U.S. immigration process comes with paperwork, case numbers, and documents you didn’t know existed until someone asked for them. One of the most important? Your Alien Registration Number.

It might just look like another line of numbers on your green card or immigration letter, but don’t ignore it. This number follows you throughout your immigration journey, from your first application to your green card… and possibly even beyond.

At Brudner Law, we help clients track, protect, and use their A-Numbers with confidence because knowing what it is and how to use it can save you serious time and stress.

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What Is an Alien Registration Number (A-Number)?

An Alien Registration Number, sometimes called an “A-Number” or listed as “USCIS#,” is a unique 7-to-9-digit number that USCIS assigns to many non-citizens. It acts as your personal file number across multiple agencies and stages of your immigration journey.

Once you’re assigned one, it stays with you for life. It’s the way U.S. immigration authorities track your case, and it’s often required when filling out applications or checking case status.

Where it shows up:

• Green card (permanent resident card)
  
  
• Employment Authorization Document (EAD)
  
  
• Asylum application paperwork
  
  
• Notices from USCIS or immigration court
  
  
• Some immigrant visa documents
  
  

If you’ve never had an A-Number assigned, that usually means you haven’t yet applied for an immigration benefit that requires it.

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Who Gets an A-Number?

Not every immigrant receives an A-Number right away, but here’s who typically does:

• Green card applicants (adjustment of status or consular processing)
  
  
• Asylum seekers
  
  
• Individuals in deportation or removal proceedings
  
  
• Recipients of certain work permits or humanitarian protections
  
  
• Immigrants with a pending or approved I-485, I-589, or similar USCIS application
  
  

If you’ve only applied for a visitor visa or are entering through ESTA, you likely won’t have an A-Number yet.

Still unsure? Here’s a breakdown from USCIS on who receives an A-Number and why.

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Where to Find Your Alien Registration Number

Think of your A-Number like your immigration ID. Once you’ve been assigned one, you’ll find it in a few places:

• Your green card (look for the “USCIS#” or “A#” on the front)
  
  
• Your EAD card, if you’ve been issued one
  
  
• Notices from USCIS, such as your I-797 receipt or approval letters
  
  
• A Notice to Appear if you’re in removal proceedings
  
  
• On your immigrant visa stamp or in a consular packet
  
  

It usually starts with the letter “A” followed by 8 or 9 digits (like A012345678). If you’re seeing different numbers on different documents, double-check that you’re using the official A-Number, not your case receipt number or application ID.

Need a visual reference? Check out Brudner Law’s guide to your A-Number.

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Why Your A-Number Matters

You might not need your A-Number every day, but when you do, it’s often time-sensitive. Here’s why it matters:

1. Application Tracking

Your A-Number helps USCIS, immigration courts, and the Department of State connect all of your applications. It’s how they identify you across systems—and how they track the status of your case.

2. Accessing Immigration Records

Your A-Number links to your A-file, a personal immigration record that includes your biometrics, application history, and government correspondence.

3. Communicating with USCIS

If you’re calling or writing to USCIS, having your A-Number ready speeds up the process—and makes sure you’re discussing the correct file.

4. Completing Future Applications

 Even after getting your green card or naturalizing, your A-Number may still come up when applying for things like a reentry permit, replacement documents, or naturalization.

It’s basically your immigration fingerprint, and it helps ensure consistency in your case.

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What to Do If You Lose Track of Your A-Number

Don’t panic if you can’t find it. It’s common for people to misplace old notices or get confused about which number is which.

Try this:

• Check your green card, EAD, or any I-797 notices
  
  
• Look for USCIS emails or online case updates that include document scans
  
  
• Ask your immigration attorney—they may have your number on file
  
  
• Contact USCIS and request a copy of your records
  
  
• As a last resort, file a Freedom of Information Act (FOIA) request to retrieve your full immigration file
  
  

You can start that process here.

Just know that FOIA requests can take time, so if you’re up against a deadline, speak to a lawyer who can help expedite the process.

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When to Get Legal Help with Your A-Number

Most of the time, once you know your A-Number, you’re good to go. But there are situations where having legal support makes a real difference:

• You lost your A-Number and need it urgently for a pending court date or application
  
  
• You’re unsure which of multiple numbers is your official A-Number
  
  
• You’re applying for a benefit and don’t know where or how to input your A-Number
  
  
• You’ve had more than one immigration case and want to verify that the full history is correct
  
  

Mix-ups here can lead to confusion, delays, or even misfiled paperwork. At Brudner Law, we help you stay organized, accurate, and in control.

Want to talk with someone now? Here’s how to reach us.

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How Brudner Law Can Help

We don’t just help with green cards and visas, we help you stay on top of the little details that hold your immigration story together. That includes organizing your case files, recovering your A-Number if it’s missing, and making sure your future applications are linked correctly.

We also handle more complicated cases involving waivers, appeals, or removal defense, where having the right A-Number can make or break your strategy. Learn more about our waivers and appeals services here.

You shouldn’t have to figure this out alone.

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Stay Informed, Stay Prepared

Your A-Number may just look like a string of digits, but it plays a major role in your immigration journey. Knowing what it is and how to use it can save you time, avoid mix-ups, and give you peace of mind.

Need help tracking it down, using it correctly, or updating your immigration records? Brudner Law is here to make it easier.

• Contact us for personal guidance.
  
  
• Check out our full resource center for more immigration tips.
  
  
• Visit our blog for answers to everyday immigration questions.

We’re here to help you stay one step ahead—every step of the way.

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