A-Number (Alien Registration Number): What USCIS Says It Is
An A-Number, also called an Alien Registration Number or Alien Number, is a unique seven-, eight- or nine-digit number that the Department of Homeland Security assigned to an alien, according to the USCIS glossary, while the Form I-589 page (Last Reviewed/Updated 10/26/2026) says it begins with the letter “A” and is followed by 8 or 9 digits. When we checked on November 2, 2026, the two USCIS documents gave different digit counts, and the Instructions for Form I-90 say it begins with an “A”.
Maintained by Archie Chang · Reviewed November 2, 2026 · Methodology & sources
Official USCIS tools
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USCIS’s definitions
The USCIS glossary entry is headed:
“A-Number/Alien Registration Number/Alien Number (A-Number or A#)”
“A unique seven-, eight- or nine-digit number that the Department of Homeland Security assigned to an alien. Also see USCIS Number.”
The Instructions for Form I-90 (edition 01/20/25) describe the number on the form:
“Item Number 1. Alien Registration Number (A-Number) (if any). Provide your A-Number. We use your A-Number to identify your immigration records. It begins with an “A” and can be found on correspondence you have received from the Department of Homeland Security (DHS) or USCIS. If you do not have an A-Number, type or print “N/A.””
The Form I-589 page (Last Reviewed/Updated 10/26/2026) words the digit count differently from the glossary. This page shows both and does not reconcile them:
“The A-Number begins with the letter “A” and is followed by 8 or 9 digits (for example, A123456789).”
A-Number, USCIS Number, Online Account Number and receipt number
| Identifier | What USCIS says | Source |
|---|---|---|
| A-Number (glossary) | Seven-, eight- or nine-digit number assigned by DHS; begins with an “A” (Instructions for Form I-90) | USCIS glossary; Instructions for Form I-90 |
| A-Number, per the Form I-589 page (10/26/2026) | The letter “A” followed by 8 or 9 digits | USCIS Form I-589 page |
| USCIS Number | 9-digit number on the front of Permanent Resident Cards issued after May 10, 2010 | USCIS glossary |
| USCIS Online Account Number | Unique identification number issued by the USCIS online filing system account; not the same as an A-Number | USCIS glossary; Instructions for Form I-90 |
| Receipt number | 13 characters: three letters followed by 10 numbers | USCIS glossary; Case Status Online page |
The glossary entry for the USCIS Number reads:
“A unique, 9-digit number assigned to an alien by the Department of Homeland Security that is listed on the front of Permanent Resident Cards (Form I-551 or Green Card) issued after May 10, 2010. See also Alien Registration Number or Alien Number.”
The USCIS glossary entries for the A-Number and the USCIS Number point to each other and do not say that the two are the same number.
Where USCIS asks for it
The Instructions for Form I-90 ask for the A-Number in Item Number 1. For the annual asylum fee, the Form I-589 page says:
“You will need your Alien Registration Number (A-Number) and the Receipt Number at the top of your AAF notice to pay the fee. NOTE: The AAF amount is adjusted each year as required by law.”
Frequently asked questions
What is an A-Number?
The USCIS glossary defines the A-Number (also called the Alien Registration Number or Alien Number) as "A unique seven-, eight- or nine-digit number that the Department of Homeland Security assigned to an alien."
How many digits is an A-Number?
The USCIS glossary says seven, eight or nine digits: "A unique seven-, eight- or nine-digit number". The Form I-589 page (Last Reviewed/Updated 10/26/2026) says: "The A-Number begins with the letter “A” and is followed by 8 or 9 digits (for example, A123456789)." The Instructions for Form I-90 say the number "begins with an “A”". The documents give different digit counts, and FedRateCalc does not reconcile them.
Where do I find my A-Number?
The Instructions for Form I-90 (Item Number 1) say it "can be found on correspondence you have received from the Department of Homeland Security (DHS) or USCIS."
What does USCIS say if I do not have an A-Number?
On Form I-90, Item Number 1, the Instructions for Form I-90 say: "If you do not have an A-Number, type or print “N/A.”"
Is the A-Number the same as the USCIS Number?
The USCIS glossary entries for the A-Number ("Also see USCIS Number") and the USCIS Number ("See also Alien Registration Number or Alien Number") point to each other and do not say that the two are the same number. The glossary describes the USCIS Number as a 9-digit number listed on the front of Permanent Resident Cards issued after May 10, 2010.
Is the A-Number the same as the Online Account Number or the receipt number?
The Instructions for Form I-90 say: "The OAN is not the same as an A-Number." The USCIS glossary defines the receipt number separately, as a 13-character identifier USCIS provides for each application or petition it receives.
When does USCIS name the A-Number for the annual asylum fee?
The uscis.gov Form I-589 page (Last Reviewed/Updated 10/26/2026) says: "You will need your Alien Registration Number (A-Number) and the Receipt Number at the top of your AAF notice to pay the fee."
Related pages
Sources
Reviewed November 2, 2026. Every number, hour, format rule and fee on this page comes from the official pages, notices and statute listed here; each quotation was compared word for word with a copy saved on November 2, 2026.