A-Number Meaning: What It Is, Where to Find It, and Uses

An A-Number, short for Alien Registration Number, is a unique seven-, eight-, or nine-digit identifier that the Department of Homeland Security assigns to a noncitizen to track that person’s entire immigration history in one file.¹ It appears on green cards, work permits, immigrant visas, and USCIS notices, usually formatted as the letter “A” followed by the digits. On documents issued after May 10, 2010, the same number is labeled “USCIS#” instead of “Alien Registration Number.” Both refer to the same thing.²

What the Number Actually Does

The A-Number is how the government keeps everything about a noncitizen in one place. When DHS assigns you a number, it also opens a permanent A-File that stores every official document connected to your immigration history. The system moved decades ago from tracking individual actions, one file per application, to tracking individual people. All your paperwork lives in a single folder identified by your A-Number.³

USCIS, Customs and Border Protection, and Immigration and Customs Enforcement all share data through A-Files. When an officer pulls up your number, they see approved petitions, denied applications, border crossings, and enforcement encounters together. The number also prevents mix-ups between people with similar names, a real and frequent issue in a system processing millions of cases.

Once assigned, the number stays with you permanently. It doesn’t change when you switch visa categories, leave the country, or naturalize.

Who Has an A-Number

USCIS creates an A-Number when someone first applies for a long-term or permanent immigration benefit. CBP and ICE assign them during enforcement actions, including to people who entered without authorization.⁴ Common situations that generate one:

Approval as a lawful permanent resident, or entry on an immigrant visa.
Filing Form I-765 for an Employment Authorization Document.
Placement in removal proceedings; the immigration court’s case system identifies each case by A-Number.
Filing for asylum or arriving as a refugee.
Receiving Temporary Protected Status.

Federal law requires the registration of noncitizens across several categories, including crewmen, border-crossing card holders, and people under order of removal.⁵

Nonimmigrants Usually Don’t Have One

Tourists, business visitors, F-1 students, and H-1B workers generally don’t get an A-Number just by entering the country. Those categories are tied to temporary stays and don’t automatically trigger the immigrant-tracking system. An H-1B approval notice on Form I-797 shows a receipt number for that petition, not a permanent A-Number.

The exception is when a nonimmigrant takes a step that signals long-term intent. An F-1 student applying for Optional Practical Training through an EAD receives an A-Number at that point if they don’t already have one. So does an H-1B holder who files an I-140 immigrant worker petition or an I-485 adjustment of status. You may also have a number from an earlier, unrelated filing, such as an old family-based petition or a prior asylum application, that you no longer remember.

Where to Find Your A-Number

The number is formatted as the letter “A” followed by eight or nine digits, for example A012345678. If yours has fewer than nine digits, add a zero after the “A” and before the first digit on any form that asks for nine digits. “A12345678” becomes “A012345678.”⁶

Look for it in these places:

Permanent Resident Card (green card): on the front, labeled “USCIS#.” Cards issued after May 2010 show a nine-digit version.²
Employment Authorization Document: on the front, labeled “USCIS#.”
Immigrant visa stamp in your passport: listed as the “Registration Number” on the visa foil.⁶
Form I-797 Notice of Action: near the top of the page.

On newer documents you won’t see the words “Alien Registration Number” spelled out. Look for “USCIS#” or “A#” instead. The underlying number is the same regardless of the label.

A-Number vs. Receipt Number

People mix these up constantly, and putting the wrong one on a form can delay your case. They do different jobs.

Your A-Number is tied to you as a person and stays the same across every application you file. A receipt number is tied to a single application. Every new filing with USCIS gets its own receipt number, so you accumulate many of those over the years while keeping only one A-Number.

The formats are also different. An A-Number is “A” plus eight or nine digits. A receipt number is 13 characters: three letters identifying the service center or filing method (for example, “IOE” for electronic filing) followed by 10 digits that encode the fiscal year, processing day, and a unique case identifier. If a field asks for your A-Number and you enter a 13-character receipt number, the system will reject it.

To check the status of a specific application, use the receipt number on the USCIS Case Status page. Your A-Number won’t pull up individual case updates there, because it spans your entire history rather than a single filing.

How to Get Your A-Number if You Can’t Find It

If no document you have shows the number, request your records from USCIS through a Freedom of Information Act or Privacy Act request. As of January 22, 2026, DHS no longer accepts mailed or emailed FOIA/Privacy Act requests. All submissions must be made online.⁷

The primary method is the USCIS FIRST portal at first.uscis.gov. Create a USCIS account and submit your request electronically.⁸ The portal lets you track status, receive notifications, and download released records. There’s no fee for a basic first-party records request. USCIS still publishes Form G-639 as a reference for the information you’ll need to provide, but online submission is the expected method.⁹

Have your full legal name, any prior names or aliases, date of birth, and country of birth ready so the system can locate your file. Processing times vary. Simple lookups may come back within weeks; complex files involving multiple agencies can take months.

Protecting Your A-Number

Treat your A-Number with the same care you’d give a Social Security number. Someone holding it along with basic biographical data could access or impersonate your immigration identity, which opens the door to fraud.

USCIS warns that scammers target immigrants through misleading offers of help, often on social media, in exchange for personal information or fees.¹⁰ A few basics worth keeping in mind:

USCIS will never ask you to send money to an individual or pay fees outside of your myUSCIS account.¹⁰
Keep your passport and identity documents in your own possession. Employers and landlords have no right to hold them.
Share the A-Number only where it belongs: on government forms, on Form I-9 employment verification, and with a licensed attorney. Requests by random email, text, or social media message are red flags.

1
U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number
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U.S. Citizenship and Immigration Services. USCIS Number
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U.S. Citizenship and Immigration Services. A-File 1 Million – The First A-File
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Department of Homeland Security. Privacy Impact Assessment for the National File Tracking System
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Office of the Law Revision Counsel. 8 USC 1303 – Registration of Special Groups
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U.S. Citizenship and Immigration Services. Immigrant Fee Payment – Tips on Finding Your A-Number and DOS Case ID
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Homeland Security. Freedom of Information Act (FOIA)
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U.S. Citizenship and Immigration Services. Request Records through the Freedom of Information Act or Privacy Act
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U.S. Citizenship and Immigration Services. USCIS Form G-639 – Freedom of Information/Privacy Act Request
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U.S. Citizenship and Immigration Services. Common Scams