What Is an Alien Registration Number (A-Number)?
Updated June 2026 · By Asal Multi Services · Columbus, OH
Quick Answer
- ✓ An A-Number (Alien Registration Number) is your personal ID number with U.S. immigration.
- ✓ It looks like A-123456789 (7–9 digits).
- ✓ Find it on your green card (labeled “USCIS#”), work permit, immigrant visa, and USCIS notices.
- ✓ It is not the same as a receipt number (which tracks one specific application).
Filling out a USCIS form and stuck on the line that asks for your “A-Number”? You are not alone — it is one of the most common points of confusion, partly because USCIS uses several different ID numbers that look similar. This guide explains what the A-Number is, exactly where to find it, and how to tell it apart from the other numbers on your documents.
What the A-Number is
The Alien Registration Number — often shortened to “A-Number” or written as “A#” — is a unique number that U.S. immigration authorities assign to an individual. It identifies youacross your entire immigration history, no matter how many different applications you file over the years. In other words, it follows the person, not the case.
What it looks like
An A-Number is typically 7, 8, or 9 digits, written with an “A” in front — for example, A-123456789. Older records sometimes have fewer than 9 digits. When a form specifically asks for 9 digits and yours is shorter, you can add zeros right after the “A” (for example, A-012345678) so the total is nine digits.
Where to find your A-Number
Look in these common places:
- • Permanent Resident Card (green card): shown as “USCIS#” — the same nine digits as your A-Number, just without the “A.”
- • Employment Authorization Document (EAD / work permit): printed on the card.
- • Immigrant visa in your passport.
- • USCIS notices and decisions (receipt notices, interview notices, approval/denial letters) often display it near the top.
- • Immigration court documents, if you have ever been in proceedings.
A-Number vs the other USCIS numbers
This is where most people get tripped up. Here is how the three most common numbers differ:
| Number | What it identifies | Example format |
|---|---|---|
| A-Number | You, across all your cases | A-123456789 |
| USCIS# (on green card) | Same as your A-Number | 123456789 |
| Receipt number | One specific application/petition | IOE0123456789 |
The key idea: your A-Number is permanent and personal. A receipt number is temporary and case-specific — you get a new one with each filing, and you use it to check that case's status on the USCIS website.
What if you don't have one?
Not everyone has an A-Number. If you have never had a green card, work permit, immigrant visa, or removal case, you may not have been assigned one yet. Many forms allow you to write “None” or “N/A” in that case. If you are unsure whether you have one, it is worth checking your old documents carefully before assuming you don't — using the wrong number, or leaving it blank when you do have one, can cause delays.
Not sure which number goes where?
Asal Multi Services prepares USCIS forms for Columbus families every day — green cards, work permits, citizenship, and family petitions. Bring your documents and we'll make sure every number is entered correctly. Somali, Arabic, and English spoken; walk-ins welcome.
Related guides
- → How Long Does U.S. Citizenship Take in 2026?
- → Green Card Renewal & Replacement (Form I-90)
- → USCIS Columbus Field Office: Interview Guide
- → Browse all Asal guides & resources
Frequently Asked Questions
What does an A-Number look like?
An A-Number (Alien Registration Number) is a 7-, 8-, or 9-digit number, usually written with an "A" in front, like A-123456789. Newer records use 9 digits; if yours is shorter, you can add leading zeros after the "A" to make 9 digits when a form requires it.
Where do I find my A-Number?
Common places include the front or back of your Permanent Resident Card (green card), your Employment Authorization Document (EAD/work permit), your immigrant visa, and most USCIS notices and decisions. On the green card it is often labeled "USCIS#," which is the same digits as your A-Number.
Is the A-Number the same as the USCIS number on my green card?
Yes. On current Permanent Resident Cards, the field labeled "USCIS#" contains the same nine digits as your Alien Registration Number, just without the "A" prefix. They refer to the same identifier.
Is my A-Number the same as my receipt number?
No. A receipt number is a 13-character code (three letters followed by numbers, like IOE0123456789) that USCIS assigns to a specific application or petition so you can track that case. Your A-Number stays with you across cases; a receipt number is tied to one filing.
Does everyone have an A-Number?
Not necessarily. A-Numbers are assigned to many people who interact with U.S. immigration — green card holders, people who applied for work permits, people in removal proceedings, and many applicants. If you have never had a relevant immigration case, you may not have one yet. Some forms let you write "None" or "N/A" if you genuinely do not have one.
What if I have two different A-Numbers?
Occasionally USCIS records show a person with more than one A-Number. This should be corrected so your immigration history is consolidated under one number. If you think you have duplicate A-Numbers, bring all your documents in and we can help you flag it for USCIS.
Asal Multi Services is a non-attorney document preparation service and does not provide legal advice. This guide is general information only. For your specific case, verify details with USCIS at uscis.gov.