The document number on a Green Card is the 13-character code printed in the machine-readable zone on the back of the card. It identifies the specific immigration case that produced your card and links the physical card to USCIS records. It is not the same as your A-Number, and knowing the difference matters when you fill out immigration forms.
Where the Number Is Printed
Flip the card over. At the bottom you’ll see two lines of letters, numbers, and angle brackets — that’s the machine-readable zone. The document number sits inside the first line, running through positions 16 to 30, right after your A-Number and a check digit.
USCIS has redesigned the card several times, and the exact position of the data fields has shifted with each version. The 13-character format itself hasn’t changed, and on every version since the format was adopted, the number lives somewhere in the machine-readable zone on the back. If you’re holding a card issued between 1977 and 1989, it may look quite different from current examples and has no expiration date printed on it.
What the 13 Characters Mean
The format is three letters followed by ten digits. Each piece tells you something about how the case was handled.
The first three letters identify the USCIS facility that processed the application:
- MSC – National Benefits Center (formerly the Missouri Service Center)
- LIN – Nebraska Service Center (formerly Lincoln)
- SRC – Texas Service Center (formerly the Southern Regional Center)
- EAC – Vermont Service Center (formerly the Eastern Adjudication Center)
- WAC – California Service Center (formerly the Western Adjudication Center)
- IOE – Cases filed electronically through the USCIS online system
If you filed online, expect an IOE prefix rather than one of the physical service center codes.1U.S. Citizenship and Immigration Services. Receipt Number
The next two digits are the federal fiscal year the case was received. The federal fiscal year runs October 1 through September 30, so a case received in November 2025 falls into fiscal year 2026 and shows “26.” This catches people out for anything filed between October and December, when the fiscal year is already one ahead of the calendar year.
The three digits after that are the workday within that fiscal year when USCIS opened the case, counting business days only. The last five digits are the unique case serial for that day and processing center. So MSC2601312345 reads as: National Benefits Center, fiscal year 2026, workday 013, case 12345.
Document Number vs. A-Number
These get mixed up constantly, and putting one where the other belongs on a form can delay your case.
Your A-Number (Alien Registration Number), also labeled “USCIS#” on newer cards, is a seven-, eight-, or nine-digit number assigned to you personally by the Department of Homeland Security.2U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number It belongs to you and stays the same for life, through every renewal, status change, and future filing. On cards issued after May 2010, the A-Number is printed on the front of the card and also appears on the back.3U.S. Citizenship and Immigration Services. 13.1 List A Documents That Establish Identity and Employment Authorization
The 13-character document number, by contrast, belongs to the card and the case that produced it. Renew your Green Card, and you get a new document number because a new case opened. Your A-Number does not change.
A rule of thumb for forms: if a field asks for your “USCIS Number” or “A-Number,” it wants the shorter number on the front. If it asks for a “card number” or “receipt number,” it wants the 13-character string from the back. Other markings on the card — a series designation, the “I-551” form identifier, internal control numbers — don’t come up in ordinary paperwork and can be ignored.
When You Actually Need the Document Number
You’ll use your A-Number far more often. The document number shows up in a smaller set of situations.
Replacing or Renewing the Card
Form I-90 (Application to Replace Permanent Resident Card) asks for the document number from your current or most recent card so USCIS can link the request to the existing record.
Form I-9 for a New Job
A Green Card is a “List A” document on Form I-9, establishing both identity and work authorization in one step.4U.S. Citizenship and Immigration Services. 7.1 Lawful Permanent Residents (LPR) Your employer records the document number as part of that verification.
SAVE Verification
State motor vehicle departments and benefits agencies verify immigration status through a federal system called SAVE (Systematic Alien Verification for Entitlements). The document number is one of the accepted identifiers (listed as “Card Number” in that system), and providing it alongside your A-Number improves the odds of an immediate response.5U.S. Citizenship and Immigration Services. Verification Process
International Travel
Airlines transmit passenger information to U.S. Customs and Border Protection under the Advance Passenger Information System. For lawful permanent residents traveling on a Green Card, the carrier may need to transmit the document number as part of the electronic manifest.6Federal Register. Advance Passenger Information System: Electronic Validation of Travel Documents
What About the N-400?
One common misconception: the naturalization application (Form N-400) does not have a field for the 13-character document number. It asks for your A-Number. You do submit a photocopy of both sides of your Green Card with the application, so the document number reaches USCIS that way, but the form itself doesn’t request it.7U.S. Citizenship and Immigration Services. M-477 Document Checklist Entering a 13-character number where a 9-digit A-Number is expected will flag an error.
Finding the Number Without the Card in Hand
If you don’t have the physical card, the number may still be recoverable from a few places.
Start with your USCIS online account at my.uscis.gov. It stores case history and receipt numbers tied to your applications, and if you filed electronically (IOE prefix) the number is almost certainly there.8U.S. Citizenship and Immigration Services. Checking Your Case Status Online
Then check any USCIS correspondence you’ve kept. Form I-797 (Notice of Action) and the approval notice for your Green Card application generally carry the receipt number for the case that produced the card.
If nothing turns up in your own files, you can request your immigration records through a Freedom of Information Act or Privacy Act request. As of January 2026, these are submitted online at first.uscis.gov. Requests for specific documents are processed much faster than requests for a full A-File, so ask for what you need rather than everything.9U.S. Citizenship and Immigration Services. Request Records through the Freedom of Information Act or Privacy Act
If you worked with an immigration attorney or accredited representative, their file will usually contain copies of your card and the associated notices. That’s often the fastest route.
Conditional Green Cards Use the Same Format
If you got permanent residence through a marriage that was under two years old at approval, or through certain investor categories, you likely hold a conditional card valid for two years rather than ten. The document number format is identical: same three-letter prefix, same 13 characters, same location on the back. What differs is the expiration date and the category code on the front (conditional residents typically see a code beginning with “C,” such as CR1). When you file Form I-751 or I-829 to remove the conditions, you’ll reference both your A-Number and your document number.
Every card version since USCIS adopted the current format keeps the document number in the machine-readable zone on the back, so the instructions above work whether your card was issued last month or a decade ago. All previously issued cards remain valid until their printed expiration date.3U.S. Citizenship and Immigration Services. 13.1 List A Documents That Establish Identity and Employment Authorization