Last Updated: April 2026
Researched by the I9AuditReady Research Team
Green Card Numbers for Form I-9: Where to Find Every Number You Need
A Permanent Resident Card (Form I-551) has four different numbers on it. Here is exactly which number goes where on Form I-9 — and the mistake that generates the most Section 2 errors.
Green Card as an I-9 Document
Document Type
Form I-551 (Permanent Resident Card)
I-9 List
List A (Identity + Work Auth)Reverification Required?
NO — never reverifyA Permanent Resident Card (Form I-551) is a List A document that establishes both identity and employment authorization for Form I-9 purposes. When an employee presents a green card, no List B or List C documents may be requested.
The Four Numbers on a Green Card
Modern Permanent Resident Cards (issued since May 2010) contain four distinct identifiers. Each serves a different purpose.
United States of America
Permanent Resident Card
Form I-551
Front of Card
Card Number (USCIS #)
Lower right — 13 chars (e.g., LIN2409012345)
A-Number
Front, below photo — 9 digits (e.g., A012345678)
Category Code
Front — e.g., IR1, F21, C09
Back of Card
Document Number
Back, lower right — also 13 chars
⚠ Often same as Card Number but verify
LIN2409012345Location on card: Front of card, lower right area
For I-9 Section 2: Enter this in 'Document Number' field in Section 2
A012345678Location on card: Front of card, below or near photo
For I-9 Section 2: NOT the document number — do not enter here
IR1, F21, C09...Location on card: Front of card, labeled 'Category'
For I-9 Section 2: Not recorded on Form I-9 — informational only
LIN2409012345Location on card: Back of card, lower right, also in MRZ
For I-9 Section 2: Same as card number on most modern cards
Which Number Goes Where on Form I-9
| Form I-9 Field | What to Enter | Where to Find It |
|---|---|---|
| Document Title | Permanent Resident Card | The card itself — or write 'Form I-551' |
| Issuing Authority | USCIS | Standard — USCIS issues all green cards |
| Document NumberMost errors here | Card number (13 chars, e.g., LIN2409012345) | Front of card, lower right |
| Expiration Date | Date printed on card (MM/DD/YYYY) | Front of card, labeled 'Card Expires' |
Key Rules Employers Must Know
Common Green Card I-9 Mistakes
Entering the A-Number as the Document Number
The Document Number field gets the card number (13 chars starting with letters). The A-Number is a 9-digit personal identifier — different field, different purpose.
Reverifying the I-9 when the green card expires
Do not reverify permanent residents. Their work authorization is permanent. Reverification for card expiration violates 8 U.S.C. § 1324b anti-discrimination rules.
Requesting additional List B/C documents alongside the green card
A green card is List A — it proves both identity AND work authorization on its own. Asking for more documents can be considered document abuse.
Accepting an expired green card
The card must be unexpired at the time of hire. An expired green card cannot be accepted for Section 2 (though the employee still has work authorization — they just need to present a different valid document).
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Start Free AuditFrequently Asked Questions
Where is the card number on a green card?
The card number on a Permanent Resident Card (Form I-551) is printed on the front of the card, typically in the lower right area. It is a 13-character alphanumeric code beginning with three letters (e.g., LIN, SRC, WAC, MSC) followed by 10 digits. This is the number you enter in Form I-9 Section 2 under 'Document Number' when the employee presents a green card.
What is the document number on a permanent resident card?
The 'Document Number' on a Permanent Resident Card refers to the card number — a 13-character alphanumeric code on the front of the card starting with three letters and followed by 10 digits. This is what you record in the Document Number field of Form I-9 Section 2. Do not confuse it with the A-Number (Alien Registration Number), which is a 9-digit number also on the card.
Is the alien number the same as the green card number?
No. The A-Number (Alien Registration Number) and the card number are two different numbers on a green card. The A-Number is a 7-to-9 digit number (e.g., A012345678) that stays with the person permanently — it identifies the individual. The card number is a 13-character code that identifies the specific card issued. For Form I-9 Section 2, enter the card number (not the A-Number) in the Document Number field.
Do I need to reverify a green card holder?
No. Employers should NOT reverify permanent residents who present a Permanent Resident Card (Form I-551) — even if the card has an expiration date. Lawful permanent residents have permanent authorization to work in the United States. Reverifying their I-9 based on card expiration is considered an unfair immigration-related employment practice under 8 U.S.C. § 1324b.
What if the green card is expired?
An expired Permanent Resident Card cannot be accepted for Form I-9 Section 2 — the document must be unexpired at the time of hire. However, once a valid green card has been used to complete I-9, employers must NOT reverify when the card expires later. The employee's work authorization is permanent even if the physical card expires. An employee with an expired card can present other acceptable I-9 documents or a Form I-797 receipt notice for a card renewal.
Can I accept a green card receipt for I-9?
You can accept a Form I-797 receipt notice for a replacement green card (when the original was lost, stolen, or damaged) as a temporary List A document for 90 days. However, a receipt for an initial application or renewal of a Permanent Resident Card is NOT acceptable for Form I-9 — only a receipt for a replacement of a previously issued card qualifies.
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Get Started FreeI9AuditReady provides compliance tracking tools, not legal advice. Information is based on USCIS Form I-9 instructions (Rev. 08/01/23) and 8 U.S.C. § 1324b. Laws and guidance can change. Consult a qualified immigration attorney for advice on your specific situation.