Your green card number is the 13-character document number printed on your Permanent Resident Card (Form I-551). It runs three letters followed by ten digits, with no spaces or dashes, and on any card issued after May 2010 you’ll find it on the back inside the machine-readable zone. A typical example looks like MSC2190012345.
What the Number Means
The format is fixed: three letters, then ten digits. USCIS uses the same format as a “receipt number” on notices of action tied to your case. The three-letter prefix identifies which USCIS office processed the application that produced your card. The ten digits encode the fiscal year the application was received, the processing day within that fiscal year, and a sequence number that separates your case from others filed the same day.1U.S. Citizenship and Immigration Services. Receipt Number
The prefix codes you’re most likely to see:
- LIN or NSC: Nebraska Service Center
- SRC or TSC: Texas Service Center
- EAC or VSC: Vermont Service Center
- WAC or CSC: California Service Center
- MSC or NBC: National Benefits Center
- IOE: cases filed or processed through the USCIS online system
IOE has become increasingly common as USCIS shifts intake to its online portal, so newer cards often carry that prefix.
Where to Find It on Your Card
On cards issued after May 2010, the document number sits on the back of the card inside the machine-readable zone. That zone is the block of small text, letters, and chevron symbols (<<<) running across the back, designed for automated scanning at border checkpoints and by employer verification systems.
Cards issued before May 2010 placed the document number on the front of the card, usually in the lower portion alongside your name and date of birth. Cards issued between January 1977 and August 1989 may not have a document number at all.2Foundation Communities. Where to Find Immigration Document Numbers A card that old is well past its validity anyway and needs to be replaced.
USCIS issued a redesigned Permanent Resident Card on January 30, 2023, with new security features and a refreshed layout. The document number is still on the back inside the machine-readable zone. The arrangement of the other data fields shifted, so if a new card doesn’t match older screenshots online, that’s why.
Reading It Correctly
The machine-readable zone packs several data points into a dense block of characters, which is where most misreads happen. Your document number is the one that starts with letters. That’s what separates it from your date of birth and the card expiration date, both purely numeric. Copy all thirteen characters exactly as printed. Unless a form specifically instructs otherwise, enter the number without spaces or dashes.
Green Card Number vs. A-Number
Your card carries two numbers that get mixed up constantly, and the difference matters because forms ask for one or the other.
The green card number (also called the document number or receipt number) identifies the physical card. It changes every time USCIS issues you a new one, because each card is tied to a new application and generates a new receipt.
The A-Number, formally the Alien Registration Number, identifies you as a person in the immigration system. It’s a seven-, eight-, or nine-digit number assigned by the Department of Homeland Security, and it stays with you for life no matter how many times your card is renewed or replaced.3U.S. Citizenship and Immigration Services. A-Number/Alien Registration Number/Alien Number
On newer cards, the A-Number appears on the front under the label “USCIS#” and again inside the machine-readable zone on the back.4U.S. Citizenship and Immigration Services. 13.1 List A Documents That Establish Identity and Employment Authorization A quick rule for filling out forms: when a government form asks for your “USCIS number,” it almost always means the A-Number, not the 13-character document number. Form N-400, the naturalization application, asks for the A-Number at the top of every page.
When You Actually Need the Green Card Number
A few common situations call for the 13-character document number specifically, rather than your A-Number.
Form I-9 Employment Verification
Every U.S. employer must verify your work eligibility on Form I-9, and a Permanent Resident Card is one of the documents that proves both identity and work authorization.5U.S. Citizenship and Immigration Services. Form I-9 Acceptable Documents The form has a document number field, and that is where your 13-character green card number goes.
Checking Case Status Online
The same 13-character string doubles as a tracking number. Enter it on the USCIS Case Status Online portal to see where a pending application stands, whether it’s a replacement, a renewal, or removal of conditions. The system accepts the number without dashes.6U.S. Citizenship and Immigration Services. Case Status Online This is especially useful after filing Form I-90 for a replacement card.
Social Security and Other Applications
When you apply for a Social Security number, Form SS-5 requires a current, unexpired Department of Homeland Security document showing your lawful status.7Social Security Administration. Application for a Social Security Card SSA works primarily from the physical card and your A-Number, but having the document number in front of you helps if any discrepancy comes up in processing.
Re-Entry Permits
If you plan to be outside the United States for more than a year and want to keep your permanent resident status, you file Form I-131 for a re-entry permit. The application requires a copy of both the front and back of your green card, which captures the document number as part of the filing. If your card is unavailable, you can substitute other evidence of lawful permanent residence, such as passport visa pages showing your initial admission or a notice of action from a pending replacement.
If You Get a New Card, You Get a New Number
Anytime USCIS issues you a replacement or renewal card through Form I-90, the new card carries a new 13-character document number. Your A-Number does not change. Any records or accounts tied to the old document number, like a pending I-9 or case status lookup, will still reference the old number until they’re updated, so keep a note of the old number for a while after your new card arrives.
If you need to travel internationally while a replacement is pending, you can request an appointment at your local USCIS office to get a temporary I-551 stamp placed in your passport. The stamp serves as proof of status until the new card arrives.
Keeping the Number Safe
Your green card number and A-Number together carry enough identifying information to cause real damage if someone else gets hold of them. Possible misuse includes opened credit accounts, fraudulent tax returns, and false identification documents. In the worst case, a thief could give your information to law enforcement during an arrest, leaving you with an unexplained record attached to your immigration file.
A few habits reduce that risk. Don’t carry the physical card unless you specifically need it that day. Keep a photocopy in a secure spot at home and, if you keep a digital scan, put it in an encrypted file rather than your regular phone photos. Before you type the number into any online form, confirm the site is a .gov domain. If your card is stolen, file a police report and then file Form I-90 promptly. Delayed reporting makes it harder to contest fraudulent activity that occurs in the meantime.