Alien Registration Number (A-Number): What It Is & Where to Find It
An Alien Registration Number (A-Number) is a unique seven- to nine-digit identifier assigned to non-U.S. citizens by the U.S. Citizenship and Immigration Services (USCIS). It is used for tracking immigration records and is required for green card applications, work permits, and other legal processes.
Where to Find Your A-Number
- Green Card (Permanent Resident Card) – Listed as the USCIS# on the front.
- Employment Authorization Document (EAD) – Located under USCIS#.
- Immigration Documents – Found on visa paperwork or notices from USCIS.
Why Is an A-Number Important?
- Required for immigration applications and petitions.
- Used to track legal status and immigration history.
- Essential for work authorization and naturalization processes.
Frequently Asked Questions
What if I lost my A-Number?
If you’ve lost your A-Number, you can find it on any official USCIS documents, immigration forms, or your green card. You can also contact USCIS directly through their website or call their customer service line to retrieve your A-Number by providing your personal information and case details.
Is the A-Number the same as a Social Security Number?
No, the A-Number and Social Security Number are completely different identifiers. The A-Number is specifically used for immigration purposes, while a Social Security Number is issued for tax and employment purposes. However, some individuals may have both if they’ve obtained work authorization.
Can I change my A-Number?
No, your A-Number is permanent and cannot be changed. It remains the same throughout your immigration journey and is tied to your immigration record. If you notice an error in your A-Number on official documents, contact USCIS to request a correction.
Do I need an A-Number to work in the United States?
While an A-Number itself doesn’t authorize work, it is required as part of the Employment Authorization Document (EAD) process. Your EAD, which displays your A-Number, is what authorizes you to work legally in the United States.
What happens to my A-Number if I become a U.S. citizen?
Your A-Number becomes inactive once you become a U.S. citizen, as you no longer need immigration-based identification. However, your historical A-Number may remain in USCIS records for administrative purposes. You will then use your Social Security Number for official identification and employment.
Related Terms
Green Card | Employment Authorization Document | USCIS
Last updated April 2026.