You can find your Alien Registration Number (A-Number) on several official immigration documents issued by U.S. Citizenship and Immigration Services (USCIS) or related agencies:

• On your permanent resident card (green card), labeled as “USCIS#” or “A#” on the front and sometimes on the back of the card

• On your Employment Authorization Document (EAD or work permit), usually under the label “USCIS#” on the front of the card

• On your immigrant visa stamp in your passport, where it appears as a nine-digit number under “Registration Number”

• On USCIS notices, such as approval notices, receipt notices, or any correspondence from USCIS, where it is typically labeled “A#” near the top of the first page

• On your immigrant data summary or USCIS Immigrant Fee handout if you applied from outside the U.S.

If you have lost all documents containing your A-Number, you can request it through the Freedom of Information Act (FOIA) system to obtain a copy of your immigration file or schedule an appointment with USCIS for assistance

. In summary, your Alien Registration Number is most commonly found on your green card, work permit, immigrant visa stamp, and official USCIS correspondence