An A-Number, also called an Alien Registration Number, is a unique number that the Department of Homeland Security assigns to a person. USCIS's glossary describes it as seven, eight or nine digits long. It is a different number from the 13-character receipt number on your notices and from the USCIS online account number. Not everyone has an A-Number: USCIS forms ask for it "if any."
What USCIS says an A-Number is
The USCIS glossary lists the terms "A-Number," "Alien Registration Number" and "Alien Number" together. It defines them as "A unique seven-, eight- or nine-digit number that the Department of Homeland Security assigned to an alien." The glossary uses the legal word "alien," and so do USCIS forms. This article uses it only when quoting.
The glossary entry does not explain how the number is assigned or when. It also does not say what the digits mean, so this article does not guess.
How many digits, and the leading zeros
Official pages describe the length in slightly different words, so it helps to see both.
- The glossary says seven, eight or nine digits.
- The Form N-400 instructions say the A-Number on a Green Card "consists of a seven- to nine-digit number, depending on when your record was created." They also say that if the number on the card has fewer than nine digits, you place enough zeros before the first number to make nine digits on the form. Their examples are A1234567 becoming A001234567 and A12345678 becoming A012345678.
- A USCIS page on finding your A-Number for the immigrant fee says the A-Number is the letter A followed by 8 or 9 numbers (such as A012345678). That page was last reviewed in 2018, so read it as guidance for that specific situation.
Where to find it
USCIS does not publish one single list. These are the places the pages we read mention.
- Green Card. The N-400 instructions say "Your A-Number is located on your Permanent Resident Card" and that it "may be located on the front or back of your card, depending on when the card was issued."
- Other secure documents. USCIS's page on correcting, updating or replacing immigration documents lists secure identity documents including Employment Authorization Documents (Form I-766) and Permanent Resident Cards (Form I-551). It says "These documents include your personal information, such as your full legal name, date of birth, country of birth, sex, and A-Number."
- Immigrant visa paperwork. For people who paid the USCIS Immigrant Fee, USCIS says you can find the A-Number "on your immigrant data summary, USCIS Immigrant Fee handout, or immigrant visa stamp." On the visa stamp, it says the A-Number "is identified as the Registration Number."
We did not find an official page that says your A-Number is printed on a particular kind of receipt notice, so this article does not claim it. Check your own paperwork.
A-Number, receipt number and online account number are three different things
| Number | What USCIS says |
|---|---|
| A-Number | "A unique seven-, eight- or nine-digit number" that DHS assigned to a person. |
| Receipt number | "a unique 13-character identifier USCIS provides for each application or petition it receives," made of 3 letters and 10 numbers, found on notices of action (glossary). |
| USCIS online account number | "a unique identification number issued by the USCIS online filing system account," with one account number for all cases submitted (glossary). |
The Form I-765 instructions state the difference directly: "The OAN is not the same as an A-Number." They also say you will only have an online account number "if you previously filed a form that has a receipt number that begins with IOE." If you filed online, they say you can find it in your account profile. If you mailed the form, they say you can find it "at the top of the Account Access Notice we sent you."
The glossary has a separate entry for the USCIS Number, "A unique, 9-digit number" listed on the front of Green Cards issued after May 10, 2010. The glossary entry points to the A-Number entry for related information, and it does not say more about how the two relate, so this article does not either. Our article on the receipt number format covers that identifier, and the GreenLight glossary explains other common terms.
Using it on forms
USCIS's Tips for Filing Forms by Mail says that when you file multiple related forms in one envelope, you should "write your name, date of birth, and A-Number (if any) exactly the same way on each form," unless you have had a legal change of name or date of birth and provide proof. The N-400 instructions ask you to put your A-Number, if any, on the top right corner of each page.
Common questions
Does everyone have an A-Number?
The USCIS pages we read do not say who does or does not have one. The Form N-400 instructions ask for it "(if any)," which indicates some applicants will not have one. For a question about your own case, an immigration attorney or an accredited representative is the right person to ask.
Is an A-Number the same as a receipt number?
No. USCIS describes the receipt number as a 13-character identifier given to each application or petition, and the A-Number as a seven-, eight- or nine-digit number assigned to a person.
Is the online account number the same as an A-Number?
No. USCIS form instructions say "The OAN is not the same as an A-Number."
My card shows fewer than nine digits. What do I do?
On Form N-400, the instructions say to add zeros before the first number to make nine digits. Other forms may have their own instructions, so follow the instructions for the form you are filing.
Official sources
- USCIS Glossary: A-Number/Alien Registration Number/Alien Number
- USCIS Glossary (A entries, including Receipt Number and USCIS Online Account Number)
- USCIS Form N-400 Instructions
- USCIS Form I-765 Instructions
- USCIS: Immigrant Fee Payment, Tips on Finding Your A-Number
- USCIS: Tips for Filing Forms by Mail
GreenLight is not affiliated with USCIS or the U.S. government. This article is for informational purposes only and does not constitute legal advice.